Snippets tagged “python”
535 snippets use this tag.
- 'pip' is not recognized as an internal or external commandPython
This error message typically occurs when the command prompt or terminal is not able to find the pip executable.
- "inconsistent use of tabs and spaces in indentation"Python
"Inkonsistente Verwendung von Tabs und Leerzeichen in Einrückung" is an error message that you may encounter when working with Python code.
- "Large data" workflows using pandasPython
Here is an example of a workflow for handling large data using the pandas library:
- "Least Astonishment" and the Mutable Default ArgumentPython
In Python, a default argument is an argument that assumes a default value if a value is not provided in the function call for that argument.
- "pip install unroll": "python setup.py egg_info" failed with error code 1Python
Here is an example of a command that could cause the error you described:
- "Unicode Error "unicodeescape" codec can't decode bytes... Cannot open text files in Python 3Python
This error occurs when trying to open a file that contains escape characters (such as \) in the file path, and the escape characters are not being properly interpreted by Python.
- Accessing the index in 'for' loopsPython
To access the index in a 'for' loop in Python, you can use the built-in 'enumerate' function.
- Add a new item to a dictionary in PythonPython
To add a new item (key-value pair) to a dictionary in Python, you can use the square brackets [] or the update() method.
- Adding a legend to PyPlot in Matplotlib in the simplest manner possiblePython
Here is a simple code snippet that demonstrates how to add a legend to a PyPlot in Matplotlib:
- Alphabet range in PythonPython
In Python, you can use the string module's ascii_lowercase and ascii_uppercase constants to get the range of lowercase and uppercase letters in the ASCII character set respectively.
- Alternatives for returning multiple values from a Python functionPython
Using a tuple:
- Append integer to beginning of list in PythonPython
To append an integer to the beginning of a list in Python, you can use the insert() method.
- Argparse optional positional arguments?Python
In Python, the argparse module can be used to specify optional positional arguments by setting the nargs parameter to '?'.
- Asking the user for input until they give a valid responsePython
To ask the user for input and repeat the prompt until they give a valid response, you can use a while loop and use a try-except block to catch any errors that may occur when trying to convert the user input to the desired data type.
- Automatically create requirements.txtPython
You can use the pip freeze command to automatically generate a requirements.txt file in Python.
- Behaviour of increment and decrement operators in PythonPython
In Python, the increment operator (++) and decrement operator (--) do not exist.
- Best way to convert string to bytes in Python 3?Python
In Python 3, you can convert a string to bytes using the bytes function.
- Best way to strip punctuation from a stringPython
One way to strip punctuation from a string is to use the str.translate() method in combination with the string.punctuation constant.
- Calling a function of a module by using its name (a string)Python
To call a function from a module by using its name as a string, you can use the importlib module.
- Cannot find module cv2 when using OpenCVPython
The error message "Cannot find module cv2" usually indicates that the OpenCV library is not installed on your system, or that Python is unable to find the library.
- Catch multiple exceptions in one line (except block)Python
In Python, you can catch multiple exceptions in a single except block by separating the exceptions with a tuple.
- Change column type in pandasPython
In pandas, you can change the data type of a column using the astype() function.
- Changing one character in a stringPython
Here is a code snippet that demonstrates how to change a single character in a string in Python:
- Changing the tick frequency on the x or y axisPython
In matplotlib, you can change the tick frequency on the x or y axis of a plot by using the set_xticks() or set_yticks() method of the Axes class.
- Check if a given key already exists in a dictionaryPython
To check if a given key already exists in a dictionary, you can use the in keyword.
- Check if a word is in a string in PythonPython
You can use the in keyword to check if a word is in a string in Python.
- Check if something is (not) in a list in PythonPython
In Python, you can check if an item is in a list using the in keyword.
- Checking whether a variable is an integer or notPython
In Python, you can check if a variable is an integer using the isinstance() function.
- Class (static) variables and methodsPython
In Python, class variables are variables that are shared by all instances of a class.
- Combine two columns of text in pandas dataframePython
In pandas, you can use the str.cat() function to combine the values of two columns of text into a single column.
- Constructing pandas DataFrame from values in variables gives ValueErrorPython
Here is an example code snippet that demonstrates the issue:
- Convert a String representation of a Dictionary to a dictionaryPython
You can use the json module in Python to convert a string representation of a dictionary to a dictionary.
- Convert a Unicode string to a string in Python (containing extra symbols)Python
You can use the .encode() method to convert a Unicode string to a string containing extra symbols in Python.
- Convert all strings in a list to intPython
In Python, you can use the map() function along with the built-in int() function to convert all strings in a list to integers.
- Convert bytes to a stringPython
To convert a byte object into a string, you can use the decode() method.
- Convert columns to string in PandasPython
To convert all columns in a Pandas DataFrame to strings, you can use the following code snippet:
- Convert date to datetime in PythonPython
You can convert a date to datetime in Python using the datetime module.
- Convert floats to ints in Pandas?Python
To convert floats to integers in Pandas, you can use the astype() function.
- Convert hex string to integer in PythonPython
You can use the int() function in Python to convert a hex string to an integer.
- Convert integer to string in PythonPython
To convert an integer to a string in Python, use the str() function.
- Convert list of dictionaries to a pandas DataFramePython
Here is an example of how to convert a list of dictionaries to a pandas DataFrame:
- Convert list to tuple in PythonPython
You can convert a list to a tuple in Python by using the built-in tuple() function.
- Convert Pandas Column to DateTimePython
To convert a column in a Pandas DataFrame to a datetime data type, you can use the pandas.to_datetime() function.
- Convert pandas dataframe to NumPy arrayPython
In pandas, you can convert a DataFrame to a NumPy array by using the values attribute.
- Convert Python dict into a dataframePython
You can use the Pandas library to convert a Python dictionary into a dataframe.
- Convert string "Jun 1 2005 1:33PM" into datetimePython
To convert the string "Jun 1 2005 1:33PM" into a datetime object, you can use the datetime module in the Python standard library.
- Converting a Pandas GroupBy output from Series to DataFramePython
Here is an example code snippet that demonstrates how to convert the output of a Pandas GroupBy operation from a Series to a DataFrame:
- Converting Dictionary to List?Python
In Python, you can convert a dictionary to a list of its keys or values using the keys() and values() methods, respectively.
- Converting from a string to boolean in PythonPython
In Python, you can use the bool() function to convert a string to a boolean.
- Converting unix timestamp string to readable datePython
You can use the datetime module in Python to convert a UNIX timestamp string to a readable date.
- Correct way to write line to file?Python
The correct way to write a line to a file in Python is to use the write() method on the file object, followed by the line you want to write.
- Count the frequency that a value occurs in a dataframe columnPython
Here is an example code snippet that counts the frequency of values in a column of a Pandas DataFrame:
- Count the number of occurrences of a character in a stringPython
You can use the .count() method to count the number of occurrences of a character in a string.
- Create a dictionary with comprehensionPython
To create a dictionary using comprehension in Python, you can use the following syntax:
- Create a Pandas Dataframe by appending one row at a timePython
Here is an example of creating a Pandas DataFrame by appending one row at a time:
- Create an empty list with certain size in PythonPython
You can create an empty list of a certain size in Python using the following methods:
- Creating a Pandas DataFrame from a Numpy array: How do I specify the index column and column headers?Python
To create a Pandas DataFrame from a Numpy array and specify the index column and column headers, you can use the pd.DataFrame() constructor and pass in the Numpy array, as well as the index, columns parameters.
- Creating a singleton in PythonPython
A singleton is a design pattern that allows you to ensure that a class has only one instance.
- Creating an empty Pandas DataFrame, and then filling itPython
Note that in above example, the DataFrame is created empty first, and then columns are added one by one using the assignment operator (=).
- Delete a column from a Pandas DataFramePython
You can delete a column from a Pandas DataFrame using the drop function.
- Delete an element from a dictionaryPython
To delete an element from a dictionary in Python, you can use the del statement.
- Deleting DataFrame row in Pandas based on column valuePython
In Pandas, you can delete a row in a DataFrame based on a certain column value by using the drop() method and passing the index label of the row you want to delete.
- Determine the type of an object?Python
To determine the type of an object in Python, you can use the type function.
- Difference between @staticmethod and @classmethodPython
In Python, a method is a function that is associated with a class.
- Difference between del, remove, and pop on listsPython
del: The del keyword is used to remove an item from a list by its index.
- Display number with leading zerosPython
You can use the str.format() method to display a number with leading zeros in Python.
- Does Django scale?Python
Django is a web framework that is designed to handle high traffic and can scale to meet the demands of a large number of users.
- Does Python have a string 'contains' substring method?Python
Yes, Python has a string method called str.__contains__() that allows you to check if a string contains another string.
- Does Python have a ternary conditional operator?Python
Yes, Python has a ternary operator, also known as the conditional operator or the ternary conditional operator.
- Does Python's time.time() return the local or UTC timestamp?Python
The time.time() function in Python returns the current timestamp in seconds since the epoch (January 1, 1970) in the local timezone.
- Dump a NumPy array into a csv filePython
Here's an example code snippet that demonstrates how to dump a NumPy array into a CSV file:
- Equivalent of shell 'cd' command to change the working directory?Python
In Python, you can use the os module to change the current working directory using the chdir() function.
- Error "Import Error: No module named numpy" on WindowsPython
This error message indicates that the Python interpreter is unable to find the numpy module, which is likely because it is not installed on your system.
- error UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start bytePython
Here is an example of how to handle a UnicodeDecodeError caused by an invalid start byte:
- error: Unable to find vcvarsall.batPython
The error: Unable to find vcvarsall.bat message is usually raised when you are trying to install a Python package that requires a C compiler, and the compiler is not installed or cannot be found by Python.
- Extract file name from path, no matter what the os/path formatPython
You can use the os.path.basename() function to extract the file name from a file path, regardless of the operating system or path format.
- Extracting extension from filename in PythonPython
You can extract the file extension from a file name in Python by using the os.path module.
- Extracting just Month and Year separately from Pandas Datetime columnPython
You can extract the month and year separately from a Pandas datetime column using the dt accessor.
- Extracting specific selected columns to new DataFrame as a copyPython
To create a new DataFrame with a subset of columns from an existing DataFrame, you can use the pandas library.
- Fastest way to check if a value exists in a listPython
The fastest way to check if a value exists in a list is to use the in operator.
- fatal error: Python.h: No such file or directoryPython
It looks like you are trying to include the Python.h header file in a C or C++ program, but it is not found on your system.
- Filter pandas DataFrame by substring criteriaPython
Here is an example of how you can filter a pandas DataFrame by substring criteria:
- Find all files in a directory with extension .txt in PythonPython
Here is a code snippet that uses the os and glob modules to find all files in a directory with the extension '.txt':
- Find the current directory and file's directoryPython
To find the current directory in Python, you can use the following code:
- Finding and replacing elements in a listPython
Here is a Python code snippet that demonstrates how to find and replace elements in a list:
- Finding local IP addresses using Python's stdlibPython
Here is a code snippet that uses the socket module from Python's standard library to find the local IP addresses of the host machine:
- Finding the average of a listPython
Here is a Python code snippet for finding the average of a list of numbers:
- Finding the index of an item in a listPython
To find the index of an item in a list in Python, you can use the index() method of the list.
- Generate random integers between 0 and 9Python
To generate a random integer between 0 and 9 in Python, you can use the random module and the randint function.
- Get a list from Pandas DataFrame column headersPython
You can use the DataFrame.columns attribute to access the column labels of a DataFrame as an Index object.
- Get difference between two lists with Unique EntriesPython
You can use the set data type to find the difference between two lists with unique entries.
- Get first row value of a given columnPython
Here's an example of how you can get the first row value of a given column in a Pandas DataFrame in Python:
- Get key by value in dictionaryPython
You can use the in keyword to check if a value exists in a dictionary, and then use the items() method to return a list of key-value pairs.
- Get list from pandas dataframe column or row?Python
In Pandas, a DataFrame is a 2-dimensional labeled data structure with columns of potentially different types.
- Get statistics for each group (such as count, mean, etc) using pandas GroupBy?Python
In pandas, you can use the groupby() method to group data by one or more columns and then use the agg() method to compute various statistics for each group.
- Get the data received in a Flask requestPython
In a Flask application, you can access the data received in a request using the request object.
- Get unique values from a list in pythonPython
In Python, you can use the set() function to get the unique values from a list.
- Getting a list of all subdirectories in the current directoryPython
Here is a code snippet in Python that gets a list of all subdirectories in the current directory:
- Getting key with maximum value in dictionary?Python
You can use the built-in max() function in Python to get the key with the maximum value in a dictionary.
- Getting the class name of an instancePython
To get the class name of an instance in Python, you can use the __class__ attribute of the object.
- Getting the index of the returned max or min item using max()/min() on a listPython
You can use the enumerate() function along with max() or min() to get the index of the maximum or minimum item in a list in Python.
- Getting today's date in YYYY-MM-DD in Python?Python
You can use the datetime module in Python to get the current date in the YYYY-MM-DD format.
- Hidden features of PythonPython
There are many hidden features of Python, some of which are not well-known even among experienced Python programmers.
- How are iloc and loc different?Python
iloc and loc are both used to select rows and columns from a Pandas DataFrame, but they work differently.
- How are lambdas useful?Python
Lambdas, also known as anonymous functions, are useful in Python because they allow you to create small, one-time use functions without having to define them with a full function statement.
- How can I access environment variables in Python?Python
You can use the os module in Python to access environment variables.
- How can I add new keys to a dictionary?Python
To add a new key-value pair to a dictionary in Python, you can use the update() method or simply assign a value to a new key using square brackets [].
- How can I check for NaN values?Python
You can use the isnan() function provided by the math module to check if a value is NaN.
- How can I compare two lists in python and return matchesPython
To compare two lists and return the matches, you can use the built-in intersection() method of the set data type.
- How can I delete a file or folder in Python?Python
To delete a file or folder in Python, you can use the os module and call the os.remove() function to delete a file, or the shutil.rmtree() function to delete a folder and all its contents.
- How can I do a line break (line continuation) in Python?Python
In Python, you can use the "" character to indicate a line continuation.
- How can I find where Python is installed on Windows?Python
To find where Python is installed on Windows, you can follow these steps:
- How can I flush the output of the print function?Python
To flush the output of the print function, you can use the flush parameter of the print function.
- How can I get a value from a cell of a dataframe?Python
You can use the .at or .iat methods to get the value of a specific cell in a DataFrame.
- How can I get list of values from dict?Python
You can use the values() method to get a list of values from a dictionary:
- How can I get the concatenation of two lists in Python without modifying either one?Python
There are a few different ways to concatenate two lists in Python without modifying either one.
- How can I import a module dynamically given the full path?Python
You can use the importlib.import_module function to import a module dynamically given the full path to the module.
- How can I install packages using pip according to the requirements.txt file from a local directory?Python
To install packages using pip from a local directory, you can use the -r option to specify the path to the requirements.txt file.
- How can I iterate over files in a given directory?Python
You can use the os module in Python to iterate over files in a given directory.
- How can I make a dictionary (dict) from separate lists of keys and values?Python
You can use the zip function to create a dictionary from separate lists of keys and values like this:
- How can I make a Python script standalone executable to run without ANY dependency?Python
One way to make a Python script standalone executable is by using the package pyinstaller.
- How can I make one python file run another?Python
To run one Python file from another, you can use the exec function or the subprocess module.
- How can I open multiple files using "with open" in Python?Python
You can open multiple files using "with open" in Python by using multiple with open statements, one for each file you wish to open.
- How can I parse a YAML file in PythonPython
To parse a YAML file in Python, you can use the yaml library.
- How can I print variable and string on same line in Python?Python
You can use the print() function in Python and use the + operator to concatenate a string and a variable.
- How can I randomly select an item from a list?Python
You can use the random module's choice function to select a random element from a list.
- How can I remove a key from a Python dictionary?Python
You can use the del statement to remove a key-value pair from a dictionary in Python.
- How can I remove a trailing newline?Python
To remove a trailing newline from a string in Python, you can use the rstrip() method.
- How can I represent an 'Enum' in Python?Python
In Python, you can represent an Enum (enumeration) by using the enum module or by creating a class that inherits from enum.Enum.
- How can I safely create a nested directory?Python
To safely create a nested directory in python, you can use the os module and the makedirs function.
- How can I use Python to get the system hostname?Python
You can use the socket module in Python to get the hostname of the system.
- How can I use threading in Python?Python
Threading is a way to run multiple threads (smaller units of a program) concurrently, in the same process.
- How can I write a `try`/`except` block that catches all exceptions?Python
You can catch all exceptions by using the Exception class in the except block, like this:
- How can the Euclidean distance be calculated with NumPy?Python
Here is a code snippet that shows how to calculate the Euclidean distance using NumPy:
- How do I access the ith column of a NumPy multidimensional array?Python
You can access the ith column of a NumPy multidimensional array by using the following syntax:
- How do I append one string to another in Python?Python
You can use the "+" operator to concatenate two strings in Python.
- How do I append to a file?Python
To append to a file in Python, you can use the "a" mode of the built-in open() function.
- How do I call a function from another .py file?Python
You can call a function from another .py file by importing the file and then calling the function.
- How do I change the size of figures drawn with Matplotlib?Python
To change the size of figures drawn with Matplotlib in Python, you can use the figure() function and set the figsize argument.
- How do I check file size in Python?Python
To check the size of a file in Python, you can use the os module to get the size of the file in bytes.
- How do I check if a list is empty?Python
To check if a list is empty in Python, you can use an if statement and the len() function.
- How do I check if a string represents a number (float or int)?Python
There are several ways to measure elapsed time in Python.
- How do I check if a variable exists?Python
In Python, you can check if a variable exists by using the globals() or locals() function to check if the variable is in the global or local namespace, respectively.
- How do I check if an object has an attribute?Python
You can use the hasattr function to check if an object has an attribute.
- How do I check if directory exists in Python?Python
You can use the os module to check if a directory exists.
- How do I check the versions of Python modules?Python
You can use the built-in "pkg_resources" module to check the version of a Python module.
- How do I check whether a file exists without exceptions?Python
Three approaches to find a file
- How do I check which version of Python is running my script?Python
There are a few ways to check which version of Python is running your script.
- How do I clone a list so that it doesn't change unexpectedly after assignment?Python
There are a few different ways to make a copy of a list in Python:
- How do I concatenate two lists in Python?Python
There are a few ways to concatenate lists in Python.
- How do I connect to a MySQL Database in Python?Python
To connect to a MySQL database in Python, you can use the mysql-connector-python library.
- How do I convert a datetime to date?Python
You can use the date() function from the datetime module in Python to convert a datetime object to just a date object.
- How do I convert all strings in a list of lists to integers?Python
Here is an example of how you might convert all strings in a list of lists to integers:
- How do I count the NaN values in a column in pandas DataFrame?Python
You can use the isna() function to create a boolean mask of the NaN values in a column, and then use the sum() function to count the number of True values in the mask.
- How do I count the occurrences of a list item?Python
There are a few ways you can count the occurrences of a list item in Python:
- How do I create a constant in Python?Python
In Python, a constant is typically defined as a variable that is assigned a value that should not be modified later on in the program.
- How do I create a list with numbers between two values?Python
Here is an example of how you might create a list of numbers between two values in python:
- How do I create multiline comments in Python?Python
In Python, you can create a multiline comment using triple quotes (either single or double) at the beginning and end of the comment.
- How do I detect whether a variable is a function?Python
In Python, you can use the built-in callable() function to check if a variable is a function.
- How do I determine the size of an object in Python?Python
You can use the sys.getsizeof() function to determine the size of an object in bytes.
- How do I do a case-insensitive string comparison?Python
You can convert both strings to lowercase or uppercase (using the lower() or upper() method) before doing the comparison.
- How do I do a not equal in Django queryset filtering?Python
You can use the exclude() method to filter out records where a certain field is not equal to a certain value.
- How do I execute a program or call a system command?Python
There are several ways to execute a program or call a system command in Python.
- How do I expand the output display to see more columns of a Pandas DataFrame?Python
You can expand the output display of a Pandas DataFrame by setting the option 'display.max_columns' in pandas.
- How do I find out my PYTHONPATH using Python?Python
You can use the sys module in Python to access the sys.path variable, which contains a list of directories that Python looks in for modules to import.
- How do I find the duplicates in a list and create another list with them?Python
In Python, one way to find duplicates in a list and create another list with them is to use a for loop and an if statement.
- How do I find the location of my Python site-packages directory?Python
You can use the site module to find the location of your Python site-packages directory.
- How do I generate all permutations of a list?Python
You can use the itertools.permutations() function to generate all permutations of a list in Python.
- How do I get a list of locally installed Python modules?Python
You can use the pip module to get a list of locally installed Python modules.
- How do I get a substring of a string in Python?Python
To get a substring of a string in Python, you can use the string[start:end] notation.
- How do I get file creation and modification date/times?Python
There are a few ways to get the file creation and modification date/times, depending on the programming language and operating system you are using.
- How do I get the current time in milliseconds in Python?Python
You can use the time module in Python to get the current time in milliseconds.
- How do I get the current time?Python
To get the current time in Python, you can use the datetime module from the standard library.
- How do I get the day of week given a date?Python
You can use the datetime module in Python to get the day of the week for a given date.
- How do I get the filename without the extension from a path in Python?Python
To get the filename without the extension from a file path in Python, you can use the os.path.splitext() function.
- How do I get the full path of the current file's directory?Python
You can use the os module to get the full path of the current file's directory.
- How do I get the last element of a list?Python
To get the last element of a list, you can use negative indexing.
- How do I get the number of elements in a list (length of a list) in Python?Python
To get the number of elements in a list in Python, you can use the len() function.
- How do I get the row count of a Pandas DataFrame?Python
You can use the shape property of the DataFrame to get the number of rows and columns.
- How do I get time of a Python program's execution?Python
To get the time it takes for a Python program to execute, you can use the time module.
- How do I import other Python files?Python
To import a Python file, you can use the import statement.
- How do I install a Python package with a .whl file?Python
To install a Python package with a .whl file, you can use the pip command.
- How do I install pip on macOS or OS X?Python
To install pip on macOS or OS X, you need to use the Terminal.
- How do I iterate through two lists in parallel?Python
You can use the zip() function to iterate through two lists in parallel.
- How do I list all files of a directory?Python
In Python, you can use the os module to list all files in a directory.
- How do I lowercase a string in Python?Python
You can use the lower() method to lowercase a string in Python.
- How do I make a flat list out of a list of lists?Python
To create a flat list out of a list of lists, you can use the itertools.chain function from the itertools module in the Python standard library.
- How do I make a time delay?Python
There are several ways to add a delay to your Python program.
- How do I make function decorators and chain them together?Python
Function decorators allow you to wrap a function in another function.
- How do I measure elapsed time in Python?Python
There are several ways to measure elapsed time in Python.
- How do I merge two dictionaries in a single expression?Python
You can use the update() method of one dictionary to merge the key-value pairs from another dictionary into it.
- How do I pad a string with zeroes?Python
You can use the zfill() method to pad a string with zeros on the left side.
- How do I parse a string to a float or int?Python
To parse a string to a float or int in Python, you can use the float() and int() functions, respectively.
- How do I parse an ISO 8601-formatted date?Python
You can use the datetime.fromisoformat() method to parse an ISO 8601-formatted date in Python.
- How do I pass a variable by reference?Python
In Python, you can pass a variable by reference by using the & operator.
- How do I print an exception in Python?Python
You can print an exception in Python by using the print() function and passing the exc variable which is the default variable name for an exception.
- How do I print colored text to the terminal?Python
You can use the termcolor module to print colored text to the terminal in Python.
- How do I print curly-brace characters in a string while using .format?Python
To print a curly brace character in a string that is being formatted with the .format() method, you will need to use double curly braces to escape the character.
- How do I print the full NumPy array, without truncation?Python
To print the full NumPy array without truncation, you can use the numpy.set_printoptions() function and set the threshold parameter to np.inf.
- How do I print the key-value pairs of a dictionary in pythonPython
You can use the items() method to print the key-value pairs of a dictionary in Python.
- How do I print to stderr in Python?Python
To print to stderr in Python, you can use the stderr attribute of the sys module:
- How do I profile a Python script?Python
There are several ways to profile a Python script:
- How do I put a variable’s value inside a string (interpolate it into the string)?Python
In Python, you can use the format() method or f-strings (available in Python 3.6 and above) to interpolate a variable's value into a string.
- How do I read CSV data into a record array in NumPy?Python
You can use the numpy.genfromtxt() function to read CSV data into a NumPy record array.
- How do I read from stdin?Python
You can read from stdin in Python using the input function.
- How do I remove a substring from the end of a string?Python
To remove a substring from the end of a string, you can use the rsplit() method and specify the substring as the delimiter.
- How do I remove duplicates from a list, while preserving order?Python
There are several ways to remove duplicates from a list while preserving order.
- How do I remove the first item from a list?Python
You can use the list method pop(index) to remove the first item in a list.
- How do I remove/delete a folder that is not empty?Python
You can use the shutil module in Python to remove a folder that is not empty.
- How do I reverse a list or loop over it backwards?Python
There are a few ways to reverse a list in Python, depending on what you want to do with the reversed list.
- How do I reverse a string in Python?Python
To reverse a string in Python, you can use the following method:
- How do I select rows from a DataFrame based on column values?Python
You can use the DataFrame.loc method to select rows from a DataFrame based on column values.
- How do I set the figure title and axes labels font size?Python
In matplotlib, you can set the font size of the figure title and axes labels using the pyplot module.
- How do I sort a dictionary by key?Python
In Python, dictionaries are unordered collections of key-value pairs.
- How do I sort a dictionary by value?Python
You can use the sorted() function and pass it the dictionary, along with the key parameter set to a lambda function that returns the value from the dictionary.
- How do I sort a list of dictionaries by a value of the dictionary?Python
To sort a list of dictionaries by a value of the dictionary, you can use the sorted() function and specify the key parameter to be a lambda function that returns the value you want to sort by.
- How do I split a list into equally-sized chunks?Python
Here is a function that takes a list and an integer n and splits the list into n equally sized chunks:
- How do I split a string into a list of characters?Python
In Python, you can use the built-in list() function to convert a string into a list of characters.
- How do I split a string into a list of words?Python
Here is an example of how to split a string into a list of words in Python:
- How do I split the definition of a long string over multiple lines?Python
You can split a string over multiple lines by using triple quotes, either ''' or """ .
- How do I terminate a script?Python
In Python, you can terminate a script by using the exit() function from the sys module.
- How do I trim whitespace from a string?Python
There are a few ways to trim whitespace from a string in Python.
- How do I trim whitespace?Python
In Python, you can use the .strip() method to remove leading and trailing whitespace from a string.
- How do I type hint a method with the type of the enclosing class?Python
In Python, you can use the self keyword to refer to the instance of the enclosing class within a method.
- How do I unload (reload) a Python module?Python
To unload a Python module, you can use the del statement to remove it from memory.
- How do I update/upgrade pip itself from inside my virtual environment?Python
To update pip itself from inside your virtual environment, you can use the following command:
- How do I upgrade the Python installation in Windows 10?Python
To upgrade the Python installation in Windows 10, you can use the pip package manager.
- How do I use a decimal step value for range()?Python
You can use the numpy library's arange() function to specify a decimal step value for the range.
- How do I use raw_input in Python 3?Python
In Python 3, the input() function can be used in place of raw_input() to read input from the user.
- How do I wait for a pressed key?Python
Here is an example of how you might wait for a key press in Python:
- How do I write JSON data to a file?Python
To write JSON data to a file in Python, you can use the json module.
- How do you extract a column from a multi-dimensional array?Python
In Python, you can extract a column from a multi-dimensional array (e.g.
- How do you get the logical xor of two variables in Python?Python
You can use the ^ operator to get the logical XOR of two variables in Python.
- How do you round UP a number?Python
In Python, you can use the ceil() function from the math module to round a number up.
- How do you test that a Python function throws an exception?Python
You can use the pytest.raises function to test that a Python function throws an exception.
- How does collections.defaultdict work?Python
collections.defaultdict is a subclass of the built-in dict class in Python.
- How does Python's super() work with multiple inheritance?Python
In Python, super() is used to call a method from a parent class.
- How does the @property decorator work in Python?Python
In Python, the @property decorator is used to define a method as a "getter" for a class property.
- How to activate virtualenv in Linux?Python
To activate a virtual environment in Linux, you can use the source command and the path to the activate script that is located in the virtual environment's bin directory.
- How to add a new column to an existing DataFrame?Python
You can add a new column to an existing pandas DataFrame by using the assign() method or the [] notation.
- How to add an empty column to a dataframe?Python
In pandas, you can add an empty column to a DataFrame using the assign() method or the insert() method.
- How to add to the PYTHONPATH in Windows, so it finds my modules/packages?Python
In Windows, you can add to the PYTHONPATH environment variable to make sure that Python can find your modules and packages.
- How to apply a function to two columns of Pandas dataframePython
To apply a function to two columns of a Pandas DataFrame, you can use the apply() method of the DataFrame and pass the function as an argument.
- How to calculate number of days between two given datesPython
To calculate the number of days between two dates, you can use the timedelta class from the datetime module.
- How to catch and print the full exception traceback without halting/exiting the program?Python
You can use the traceback module to catch and print the full exception traceback without halting/exiting the program.
- How to change a string into uppercase?Python
In Python, you can use the built-in upper() method to change a string to uppercase.
- How to change the figure size of a seaborn axes or figure level plotPython
You can change the figure size of a Seaborn plot by using the set_size_inches() method of the matplotlib.pyplot.figure object and passing in the desired width and height.
- How to change the font size on a matplotlib plotPython
There are a couple of ways to change the font size on a matplotlib plot.
- How to change the order of DataFrame columns?Python
To change the order of columns in a Pandas DataFrame, you can use the DataFrame's "reindex" method and specify the new order of the columns.
- How to check if a string is a substring of items in a list of stringsPython
You can use a for loop to iterate through the list of strings, and then use the in keyword to check if the string is a substring of the current item in the list.
- How to check if any value is NaN in a Pandas DataFramePython
You can use the isna() method to check for NaN values in a Pandas DataFrame.
- How to check if the string is empty?Python
To check if a string is empty in Python, you can use the len() function or an if statement.
- How to check if type of a variable is string?Python
You can use the type() function in Python to check the type of a variable.
- How to clear the interpreter console?Python
There are a few ways to clear the interpreter console in Python, depending on the specific environment you are using.
- How to comment out a block of code in PythonPython
In Python, you can comment out a block of code by using the "#" symbol at the beginning of each line.
- How to concatenate (join) items in a list to a single stringPython
You can use the join() method to concatenate (join) items in a list to a single string in Python.
- How to convert index of a pandas dataframe into a columnPython
To convert the index of a pandas DataFrame into a column, you can use the reset_index() function, and specify that you want to move the index to a new column with the inplace=True and name parameter.
- How to convert list to stringPython
You can use the join() method to convert a list of strings to a single string.
- How to convert string representation of list to a listPython
You can use the ast.literal_eval() function from the ast module to safely evaluate a string and convert it to a list.
- How to copy a dictionary and only edit the copyPython
There are a few ways to copy a dictionary in Python, depending on the level of copying that you need.
- How to copy filesPython
To copy a file in Python, you can use the built-in "shutil" module.
- How to create a GUID/UUID in PythonPython
You can use the uuid module in Python to generate a globally unique identifier (GUID), also known as a universally unique identifier (UUID).
- How to crop an image in OpenCV using PythonPython
You can use the cv2.imread() function to read an image into memory, and then use the cv2.rectangle() function to draw a rectangle around the region you want to crop.
- How to deal with SettingWithCopyWarning in PandasPython
The "SettingWithCopyWarning" in pandas is raised when you try to modify a copy of a DataFrame or Series rather than the original.
- How to declare and add items to an array in Python?Python
To declare an array in Python, you can use the array module.
- How to define a two-dimensional array?Python
A two-dimensional array in Python can be defined using the numpy library.
- How to delete a character from a string using PythonPython
You can use string slicing to remove a specific character from a string in Python.
- How to determine a Python variable's type?Python
In Python, you can determine the type of a variable by using the type() function.
- How to disable Python warnings?Python
There are a few different ways to disable warnings in Python, depending on the specific warning and the scope in which you want to suppress it.
- How to download a file over HTTP?Python
Import the "urllib" module:
- How to drop rows of Pandas DataFrame whose value in a certain column is NaNPython
You can drop rows of a Pandas DataFrame that have a NaN value in a certain column using the dropna() function.
- How to emulate a do-while loop?Python
In Python, you can emulate a do-while loop by using a while True loop with a break statement.
- How to extract numbers from a string in Python?Python
In Python, you can use regular expressions to extract numbers from a string.
- How to extract the substring between two markers?Python
In Python, you can use the str.find() method to find the index of the first marker, and the str.rfind() method to find the index of the second marker.
- How to filter Pandas dataframe using 'in' and 'not in' like in SQLPython
You can filter a Pandas DataFrame using the isin() and ~(not in) methods.
- How to find which version of TensorFlow is installed in my system?Python
You can use the following code snippet to check which version of TensorFlow is installed in your system:
- How to fix "Attempted relative import in non-package" even with __init__.pyPython
The "Attempted relative import in non-package" error occurs when attempting to use a relative import within a script that is not part of a package.
- How to fix: "UnicodeDecodeError: 'ascii' codec can't decode byte"Python
The "UnicodeDecodeError: 'ascii' codec can't decode byte" error occurs when trying to decode non-ASCII bytes using the ASCII codec.
- How to get a function name as a string?Python
In Python, you can use the built-in function attribute __name__ to get the name of a function as a string.
- How to get all possible combinations of a list’s elements?Python
You can use the itertools library in Python to get all possible combinations of a list's elements.
- How to get an absolute file path in PythonPython
You can use the os.path.abspath() function to get the absolute file path of a file in Python.
- How to get line count of a large file cheaply in Python?Python
You can use the line_count() function from the itertools module to get the line count of a large file cheaply in Python.
- How to get the ASCII value of a characterPython
To get the ASCII value of a character in Python, you can use the built-in ord() function.
- How to get the last day of the month?Python
You can use the calendar.monthrange() function from the calendar module in Python to get the last day of a month.
- How to get the position of a character in Python?Python
You can use the index() method to get the position of a specific character in a string.
- How to identify which OS Python is running on?Python
You can use the platform module in Python to identify which operating system the code is running on.
- How to import the class within the same directory or sub directory?Python
In Python, you can use the import statement to import a module or class from a file within the same directory or a subdirectory.
- How to initialize a two-dimensional array in Python?Python
You can use the built-in list function to create a 2D array (also known as a list of lists) in Python.
- How to install PIL with pip on Mac OS?Python
To install PIL (Python Imaging Library) using pip on Mac OS, you can use the following command in your terminal:
- How to install pip with Python 3?Python
To install pip with Python 3, you can use the following command:
- How to iterate over rows in a DataFrame in PandasPython
You can use the iterrows() method to iterate over rows in a Pandas DataFrame.
- How to leave/exit/deactivate a Python virtualenvPython
To leave a Python virtual environment, you can use the deactivate command.
- How to list all functions in a module?Python
To list all functions in a module, you can use the dir() function to get a list of all the names defined in the module, and then use the inspect module to check if each name is a function.
- How to make a class JSON serializablePython
In order to make a class JSON serializable in Python, you need to define two methods: __init__ and to_json.
- How to make IPython notebook matplotlib plot inlinePython
To make matplotlib plots show up inline in an IPython notebook, you can use the following code snippet:
- How to move a file in Python?Python
In Python, you can use the shutil module to move a file.
- How to normalize a NumPy array to a unit vector?Python
To normalize a NumPy array to a unit vector, you can use the numpy.linalg.norm function to calculate the magnitude of the vector, and then divide the array by this magnitude.
- How to overcome "datetime.datetime not JSON serializable"?Python
One way to overcome "datetime.datetime not JSON serializable" in Python is to use the json.dumps() method with the default argument, default=str, which converts the datetime object to a string before serializing.
- How to parse XML and get instances of a particular node attribute?Python
You can use the xml library in Python to parse XML and get instances of a particular node attribute.
- How to POST JSON data with Python Requests?Python
You can use the requests library in Python to send a POST request with JSON data.
- How to prettyprint a JSON file?Python
To pretty-print a JSON file in Python, you can use the json module.
- How to print a date in a regular format?Python
In Python, you can use the datetime module to work with dates and times.
- How to print a dictionary's key?Python
To print the keys of a dictionary in Python, you can use the built-in keys() method.
- How to print a number using commas as thousands separatorsPython
In Python, you can use the built-in function format() to print a number with commas as thousands separators.
- How to print instances of a class using print()?Python
To print instances of a class using the built-in print() function, you can define a __str__ method within the class.
- How to print without a newline or spacePython
To print without a newline in Python, you can use the end argument for the print() function.
- How to properly ignore exceptionsPython
It's generally not recommended to ignore exceptions, as they often indicate a problem in the code that should be addressed.
- How to put the legend outside the plotPython
In matplotlib, the legend function allows you to specify the location of the legend.
- How to read a file line-by-line into a list?Python
To read a file line-by-line into a list, you can use the following approach:
- How to read a text file into a list or an array with PythonPython
One way to read a text file into a list or an array with Python is to use the split() method.
- How to read a text file into a string variable and strip newlines?Python
In Python, you can read a text file into a string variable and strip newlines using the following code:
- How to remove an element from a list by indexPython
To remove an element from a list by index in Python, you can use the pop() method.
- How to remove items from a list while iterating?Python
It is generally not recommended to remove items from a list while iterating over it because it can cause unexpected behavior.
- How to replace NaN values by Zeroes in a column of a Pandas Dataframe?Python
You can replace NaN values in a column of a Pandas Dataframe by using the fillna() method and passing in the value you want to replace NaN with.
- How to retrieve a module's path?Python
You can use the __file__ attribute of a module to retrieve its path.
- How to return dictionary keys as a list in Python?Python
In Python, you can use the dict.keys() method to return a view object that contains the keys of a dictionary.
- How to round to 2 decimals with Python?Python
You can use the built-in round() function to round a decimal to a specific number of decimal places in Python.
- How to search and replace text in a file?Python
There are several ways to search and replace text in a file, depending on the programming language you are using.
- How to search for a string in text files?Python
Here's a Python code snippet that demonstrates how to search for a string in all text files in a directory:
- How to serve static files in FlaskPython
To serve static files in Flask, you will need to use the send_static_file method in your route function.
- How to set environment variables in Python?Python
In Python, you can set environment variables using the os module.
- How to set the current working directory?Python
You can set the current working directory in Python using the os module, specifically the chdir() function.
- How to set the y-axis limitPython
In matplotlib, you can set the limit of the y-axis of a plot by using the set_ylim() method of the Axes class.
- How to sort a list of objects based on an attribute of the objects?Python
You can use the sort method of a list and pass in a key argument, which is a function that takes an object and returns the value on which you want to sort the list.
- How to sort a list/tuple of lists/tuples by the element at a given index?Python
You can use the sorted() function with the key parameter to specify a function that extracts the element at the desired index.
- how to sort pandas dataframe from one columnPython
To sort a Pandas DataFrame based on the values in a column, you can use the sort_values() method of the DataFrame.
- How to stop/terminate a python script from running?Python
There are several ways to stop a Python script from running:
- How to subtract a day from a date?Python
You can use the datetime module in Python to subtract a day from a date.
- How to test multiple variables for equality against a single value?Python
In Python, you can test multiple variables for equality against a single value using the == operator.
- How to uninstall Python 2.7 on a Mac OS X 10.6.4?Python
To uninstall Python 2.7 on a Mac OS X 10.6.4, you can use the following commands in the terminal:
- How to upgrade all Python packages with pip?Python
You can use the pip freeze command to generate a requirements file that includes all of the current packages and their versions, and then use pip install -r to upgrade all packages to the latest available versions.
- How to urlencode a querystring in Python?Python
You can use the urllib.parse.urlencode() function to urlencode a querystring in Python.
- How to use glob() to find files recursively?Python
You can use the glob.glob() function from the glob module to search for files recursively.
- How to use multiprocessing pool.map with multiple argumentsPython
To use the multiprocessing.pool.map() function with multiple arguments, you will need to use the starmap() method instead.
- How to write inline if statement for print?Python
Inline if statements, also known as ternary operators, can be used to write a shorthand version of an if-else statement.
- I'm getting Key error in pythonPython
A KeyError in Python is raised when a dictionary key is not found in the dictionary.
- if else in a list comprehensionPython
Here's an example of using an if-else statement within a list comprehension:
- If Python is interpreted, what are .pyc files?Python
.pyc files are compiled bytecode files that are generated by the Python interpreter when a .py file is imported.
- if/else in a list comprehensionPython
Here is an example of using an if/else statement in a list comprehension in Python:
- Import a module from a relative pathPython
To import a module from a relative path in Python, you can use the importlib.import_module() function from the importlib module.
- Import error: No module name urllib2Python
It looks like you are trying to import the urllib2 module, which is not available in Python 3.
- ImportError: No module named matplotlib.pyplotPython
This error message occurs when the matplotlib.pyplot module is not installed or not imported properly in your Python environment.
- ImportError: No module named PILPython
Here is a code snippet that demonstrates how to catch the "ImportError: No module named PIL" error:
- ImportError: No module named pipPython
Here is a code snippet that demonstrates how to handle the "No module named pip" error:
- ImportError: No module named requestsPython
This error message indicates that the "requests" module, which is used for making HTTP requests in Python, is not installed on your system or is not in the Python path.
- Importing files from different folderPython
To import a module from a different folder in Python, you can use the sys.path.append() function to add the path to the folder containing the module to your Python path.
- Importing modules from parent folderPython
In Python, you can use the sys.path.append() method to add the parent directory to the list of paths where Python looks for modules.
- In Python, how do I convert all of the items in a list to floats?Python
You can use a for loop and the float() function to convert each item in a list to a float.
- In Python, how do I determine if an object is iterable?Python
In Python, an object is considered iterable if it has an __iter__() method defined or if it has a __getitem__() method with defined indices (i.e., it can be indexed, like a list or a string).
- IndentationError: unindent does not match any outer indentation levelPython
This error occurs when there is a mismatch in the indentation level of a block of code in Python.
- Installing specific package version with pipPython
To install a specific version of a package with pip, you can use the pip install command followed by the package name and the desired version number.
- Is arr.__len__() the preferred way to get the length of an array in Python?Python
No, in python the built-in len() function is the preferred way to get the length of an array, list or any other iterable object.
- Is it possible to break a long line to multiple lines in Python?Python
Yes, it is possible to break a long line of code into multiple lines in Python.
- Is there a "not equal" operator in Python?Python
Yes, in Python there is an operator for not equal (!=) .
- Is there a built-in function to print all the current properties and values of an object?Python
In Python, you can use the built-in function vars() to print the properties and values of an object.
- Is there a list of Pytz Timezones?Python
Yes, you can use the all_timezones attribute of the pytz library to get a list of all the timezones that it supports.
- Is there a simple way to delete a list element by value?Python
Yes, you can use the remove() method to delete a list element by its value.
- Is there a way to run Python on Android?Python
Yes, there are several ways to run Python on Android:
- Is there any way to kill a Thread?Python
Yes, there are a few ways to kill a thread in Python.
- Iterating over dictionaries using 'for' loopsPython
To iterate over a dictionary using a for loop, you can use the .items() method to get a list of the dictionary's keys and values, and then iterate over that list.
- Limiting floats to two decimal pointsPython
To limit a float to two decimal points, you can use the round() function.
- List attributes of an objectPython
In Python, you can use the built-in function dir() to list the attributes of an object.
- List comprehension vs mapPython
List comprehension and map() are both used to create new lists in Python, but they are used in slightly different ways.
- List comprehension vs. lambda + filterPython
List comprehension and the combination of lambda functions and the filter() function in Python are both used to filter a list and return a new list with only the elements that satisfy a certain condition.
- List of lists changes reflected across sublists unexpectedlyPython
In Python, when you create a list of lists and modify one of the sublists, the change is reflected in all other sublists as well because they are all pointing to the same object in memory.
- Manually raising (throwing) an exception in PythonPython
In Python, you can raise an exception using the raise statement.
- Matplotlib make tick labels font size smallerPython
Here is a code snippet that shows how to make the tick labels font size smaller in Matplotlib:
- Maximum and Minimum values for intsPython
In most modern programming languages, the maximum value for an int data type is implementation-specific, but is typically in the range of 2^31 - 1 to 2^63 - 1, and the minimum value is usually -2^31 or -2^63.
- Meaning of @classmethod and @staticmethod for beginnerPython
In Python, @classmethod is a decorator that is used to define a method as a class method.
- mkdir -p functionality in PythonPython
The os.makedirs() function in Python can be used to create a directory with the -p option, which will create the entire directory path, including any missing parent directories.
- Most efficient way to map function over numpy arrayPython
There are several ways to apply a function to every element of a numpy array, and the most efficient method will depend on the size and shape of the array, as well as the complexity of the function.
- Multiprocessing vs Threading PythonPython
Here is a code snippet for multiprocessing in Python:
- not None test in PythonPython
In Python, you can check if a variable is not equal to None using the is not operator.
- Null object in PythonPython
In Python, the "null" object is called None.
- open() in Python does not create a file if it doesn't existPython
Here is a code snippet that demonstrates how to use the open() function in Python to create a new file if it does not already exist:
- Pandas DataFrame Groupby two columns and get countsPython
Here is an example code snippet that demonstrates how to use the groupby() method in pandas to group a DataFrame by two columns and get the counts for each group:
- Pandas index column title or namePython
To set the name of the index column in a pandas DataFrame, you can use the .rename_axis() method or the .index.name attribute.
- Pandas Merging 101Python
Here is an example of how to use the pd.merge() function to merge two DataFrames in pandas:
- Parsing boolean values with argparsePython
Here is an example of how to parse boolean values with argparse in Python:
- Peak detection in a 2D arrayPython
Here is an example of a Python function that can be used to detect peaks in a 2D array:
- pg_config executable not foundPython
Check the location of pg_config: Open a terminal and run the command "which pg_config".
- pip install fails with "connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:598)"Python
This error message occurs when pip is unable to verify the certificate of the website it is trying to connect to.
- pip install from git repo branchPython
You can use pip to install a package from a git repository and specify a branch by using the following syntax:
- pip install mysql-python fails with EnvironmentError: mysql_config not foundPython
This error occurs when the mysql-config command is not in the system's PATH.
- pip uses incorrect cached package version, instead of the user-specified versionPython
Here is an example of how to use pip to install a specific version of a package, rather than using a cached version:
- Plot logarithmic axesPython
Here is a code snippet that shows how to plot a graph with logarithmic scales for both the x and y axes in Python using the Matplotlib library:
- Pretty-print an entire Pandas Series / DataFramePython
You can use the .head() method to print the first few rows of a Pandas Series or DataFrame in a "pretty" format.
- Print multiple arguments in PythonPython
Here is an example of how to print multiple arguments in Python:
- Print string to text filePython
In Python, you can use the built-in open() function to create a text file and write a string to it.
- Printing Lists as Tabular DataPython
Here is an example of how to print a list of lists (a 2D list) as tabular data using Python:
- Proper way to declare custom exceptions in modern Python?Python
To declare a custom exception in Python, you can create a new class that inherits from the built-in Exception class.
- Purpose of "%matplotlib inline"Python
The purpose of "%matplotlib inline" in Python is to display matplotlib plots within the Jupyter notebook.
- Putting a simple if-then-else statement on one linePython
In Python, you can put a simple if-then-else statement on one line using the ternary operator, which is represented by the "?" symbol.
- Python - Count elements in listPython
You can use the len() function to count the number of elements in a list.
- Python - TypeError: 'int' object is not iterablePython
This error message is indicating that you are trying to iterate over an object of type 'int', which is not iterable (i.e.
- Python `if x is not None` or `if not x is None`?Python
The proper way to check if a variable x is not None in Python is to use if x is not None.
- Python 3: UnboundLocalError: local variable referenced before assignmentPython
This error occurs when you are trying to access a variable before it has been assigned a value.
- python exception message capturingPython
To capture an exception message in Python, you can use a try-except block and the as keyword to assign the exception message to a variable.
- Python int to binary string?Python
You can use the built-in bin() function to convert an integer to a binary string in Python.
- Python integer incrementing with ++Python
Python does not have a ++ operator for incrementing integers like some other programming languages.
- Python list of dictionaries searchPython
Here is a code snippet that demonstrates how to search for a specific value in a list of dictionaries in Python:
- python numpy ValueError: operands could not be broadcast together with shapesPython
The ValueError: operands could not be broadcast together with shapes error occurs in NumPy when the shapes of the arrays being operated on are incompatible.
- Python Pandas: Get index of rows where column matches certain valuePython
You can use the .loc method to filter the DataFrame and get the boolean mask, and then use the .index property to get the index of the rows that match the certain value.
- Python Requests throwing SSLErrorPython
Here's a code snippet that demonstrates how to use the Python requests library to make a GET request to a URL, while handling a possible SSLError:
- python setup.py uninstallPython
The command python setup.py uninstall is not a built-in command in Python and it may not work as expected.
- Python string.replace regular expressionPython
You can use the re module in Python to use regular expressions with the replace() method.
- Python: Find in listPython
Here is a code snippet that demonstrates how to find an element in a list in Python:
- Python: finding an element in a listPython
To find an element in a list, you can use the in keyword.
- python: SyntaxError: EOL while scanning string literalPython
This error message is indicating that there is a problem with a string in your code.
- Python's equivalent of && (logical-and) in an if-statementPython
In Python, the logical "and" operator is represented by the and keyword.
- Random string generation with upper case letters and digitsPython
Here is a simple function that generates a random string of a given length using upper case letters and digits:
- Reading binary file and looping over each bytePython
Here is an example code snippet that demonstrates how to read a binary file and loop over each byte in Python:
- Reading JSON from a filePython
Here is an example of reading a JSON file in Python:
- Relative imports in Python 3Python
Relative imports in Python 3 allow you to import modules or functions from other packages within your package hierarchy.
- Remove all special characters, punctuation and spaces from stringPython
Here is an example of code that removes all special characters, punctuation, and spaces from a string in Python:
- Remove all whitespace in a stringPython
You can remove all whitespace in a string in Python by using the replace() method and replacing all whitespace characters with an empty string.
- Remove empty strings from a list of stringsPython
This code uses a list comprehension to iterate through the original list and only keep the elements that are not empty strings.
- Remove final character from stringPython
You can remove the final character from a string in Python using string slicing.
- Remove specific characters from a string in PythonPython
In Python, you can remove specific characters from a string by using the replace() method or using string slicing and concatenation.
- Removing duplicates in listsPython
There are a few ways to remove duplicates from a list in Python.
- Renaming column names in PandasPython
To rename the column names of a Pandas DataFrame, you can use the DataFrame.rename() method.
- Replacements for switch statement in Python?Python
Here are a few alternatives to using a switch statement in Python:
- Reverse / invert a dictionary mappingPython
Here's an example of how you can reverse or invert a dictionary mapping in Python:
- Running shell command and capturing the outputPython
In Python, you can use the subprocess module to run shell commands and capture their output.
- Running unittest with typical test directory structurePython
Here is an example of how you can run unittests in Python using the typical test directory structure:
- Save plot to image file instead of displaying it using MatplotlibPython
To save a plot to an image file using Matplotlib, you can use the savefig function.
- Selecting a row of pandas series/dataframe by integer indexPython
You can use the .iloc[] property to select a row by its integer index in a pandas DataFrame or Series.
- Selecting multiple columns in a Pandas dataframePython
To select multiple columns in a pandas DataFrame, you can pass a list of column names to the indexing operator [].
- Selenium using Python - Geckodriver executable needs to be in PATHPython
If you are using Selenium with the Firefox web browser and you see the error message "Geckodriver executable needs to be in PATH," it means that the Selenium Python library cannot find the geckodriver executable on your system.
- Set value for particular cell in pandas DataFrame using indexPython
In pandas, you can set the value of a specific cell in a DataFrame using the at method.
- Should I put #! (shebang) in Python scripts, and what form should it take?Python
You should include a shebang (#!) in Python scripts if you want the script to be directly executable from the command line.
- Should I use 'has_key()' or 'in' on Python dicts?Python
It is recommended to use the in keyword to check if a key exists in a Python dict, rather than the has_key() method.
- Shuffling a list of objectsPython
The random module in Python provides a function called shuffle() which can be used to shuffle the elements of a list.
- Split string on whitespace in PythonPython
You can use the split() method to split a string on whitespace in Python.
- Split string with multiple delimiters in PythonPython
You can use the re.split() function from the re module in Python to split a string using multiple delimiters.
- Static methods in Python?Python
In Python, a static method is a method that belongs to a class rather than an instance of the class.
- String formatting: % vs. .format vs. f-string literalPython
In Python, there are several ways to format strings.
- Styling multi-line conditions in 'if' statements?Python
In Python, there are a few different ways to style multi-line conditions in if statements, depending on the complexity of the condition and personal preference.
- Sum a list of numbers in PythonPython
Here is a code snippet that demonstrates how to sum a list of numbers in Python:
- SyntaxError: unexpected EOF while parsingPython
The SyntaxError: unexpected EOF while parsing error is raised when the Python interpreter reaches the end of the file (EOF) while it is still parsing the file, and it is unable to complete the parsing process because of an error in the syntax of the code.
- Traverse a list in reverse order in PythonPython
You can use the reversed() function to iterate through a list in reverse order.
- Truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all()Python
The truth value of a Series in pandas can be ambiguous, as it can contain multiple values.
- TypeError: 'module' object is not callablePython
This error message typically occurs when you are trying to call a module as if it were a function.
- TypeError: 'NoneType' object is not iterable in PythonPython
The TypeError: 'NoneType' object is not iterable error message is raised when you are trying to iterate over an object that has a value of None, which is not iterable.
- TypeError: a bytes-like object is required, not 'str' when writing to a file in Python 3Python
This error occurs when you are trying to write a string to a file using the write() method in Python 3, but the file is opened in binary mode (using the 'b' flag when opening the file).
- TypeError: list indices must be integers or slices, not strPython
This error is usually caused when you try to access an element in a list using a string as the index, rather than an integer.
- TypeError: method() takes 1 positional argument but 2 were givenPython
This error message is indicating that a method or function called "method" is expecting one argument, but it was called with two arguments.
- TypeError: Missing 1 required positional argument: 'self'Python
This error message is indicating that a class method is being called without providing the "self" parameter, which is the first parameter for all class methods and refers to the instance of the class.
- Understanding Python super() with __init__() methodsPython
The super() function is a way to refer to the parent class and its attributes.
- Understanding slicingPython
In Python, slicing refers to taking a subset of a sequence (such as a list, string, or tuple) by using indices to specify the start and end points of the slice.
- Unicode (UTF-8) reading and writing to files in PythonPython
To read a file in Unicode (UTF-8) encoding in Python, you can use the built-in open() function, specifying the encoding as "utf-8".
- UnicodeDecodeError, invalid continuation bytePython
Here is an example of a Python code snippet that could cause a UnicodeDecodeError: invalid continuation byte error:
- UnicodeDecodeError: 'charmap' codec can't decode byte X in position Y: character maps to <undefined>Python
This error occurs when trying to decode a string using the 'charmap' codec, which is typically used for Windows-1252 character encoding.
- UnicodeDecodeError: 'utf8' codec can't decode byte 0x9cPython
This error occurs when a file or string that is being decoded using the UTF-8 encoding contains an invalid byte sequence.
- UnicodeDecodeError: 'utf8' codec can't decode byte 0xa5 in position 0: invalid start bytePython
This error occurs when trying to decode a byte string using the UTF-8 codec and the byte at the given position is not a valid start byte for a UTF-8 encoded character.
- UnicodeEncodeError: 'ascii' codec can't encode character u'\xa0' in position 20: ordinal not in range(128)Python
This error is raised when trying to encode a Unicode string using the ASCII codec, and the string contains a character that is not within the ASCII range (0-127).
- Unzipping files in PythonPython
Here is a code snippet that demonstrates how to unzip a file using the zipfile module in Python:
- Usage of __slots__?Python
__slots__ is a way to specify a fixed set of attributes for a class, which can help to save memory in certain situations.
- Use a list of values to select rows from a Pandas dataframePython
You can use the .loc property of a Pandas dataframe to select rows based on a list of values.
- Use different Python version with virtualenvPython
To use a different Python version with virtualenv, follow these steps:
- Use of *args and **kwargsPython
In Python, *args and **kwargs are special keywords that allow you to pass a variable number of arguments to a function.
- Using global variables in a functionPython
In Python, you can use global variables in a function by declaring the variable as global within the function.
- Using Python 3 in virtualenvPython
Here is an example of how you can use Python 3 in a virtual environment using the virtualenv package:
- UTF-8 byte[] to StringJava
To convert a byte array to a string in UTF-8 encoding, you can use the following method in Java:
- ValueError: could not convert string to float: idPython
This error message is indicating that the program is trying to convert a string to a float, but the string is not a valid number.
- ValueError: invalid literal for int() with base 10:Python
In this code snippet, the variable "value" is being set to the integer representation of the string "invalid." However, "invalid" is not a valid integer, so the int() function will raise a ValueError.
- ValueError: setting an array element with a sequencePython
This code creates a 2D numpy array, and then tries to set the first element of the array to a list.
- ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()Python
This error message is indicating that a boolean operation was performed on an array with multiple elements, and the result of the operation is ambiguous.
- What are "named tuples" in Python?Python
"Named tuples" in Python are a subclass of the built-in tuple type, but with the added ability to access elements by name rather than just by index.
- What are metaclasses in Python?Python
In Python, a metaclass is a class that defines the behavior of a class. When you create a class, Python automatically creates a metaclass for you behind the scenes. You can think of a metaclass as a blueprint for creating a class.
- What are the differences between the urllib, urllib2, urllib3 and requests module?Python
urllib, urllib2, and urllib3 are all Python standard library modules for handling URLs.
- What are the differences between type() and isinstance()?Python
In Python, type() is a built-in function that returns the type of an object, while isinstance() is a function that checks whether an object is an instance of a particular class or of a subclass thereof.
- What are the most common Python docstring formats?Python
There are several common formats for Python docstrings, including:
- What can I do about "ImportError: Cannot import name X" or "AttributeError: ... (most likely due to a circular import)"?Python
This error typically occurs when there is a circular import between two or more modules.
- What do __init__ and self do in Python?Python
__init__ is a special method in Python classes, also known as a constructor.
- What does __all__ mean in Python?Python
In Python, __all__ is a list of strings that defines the names that should be imported when from <module> import * is used.
- What does -> mean in Python function definitions?Python
In Python, the "->" symbol is used to indicate the return type of a function.
- What does "SyntaxError: Missing parentheses in call to 'print'" mean in Python?Python
The "SyntaxError: Missing parentheses in call to 'print'" error message is raised when you are using Python 3 and you have forgotten to include the parentheses when calling the print() function.
- What does ** (double star/asterisk) and * (star/asterisk) do for parameters?Python
In Python, the double star (**) is used to denote an "unpacking" operator, which allows you to unpack a dictionary or other iterable data type into keyword arguments in a function call.
- What does %s mean in a Python format string?Python
In a Python format string, the %s placeholder represents a string.
- What does functools.wraps do?Python
functools.wraps is a decorator that can be used to modify a function or method by updating its metadata.
- What does if __name__ == "__main__": do?Python
The special __name__ variable in Python is a string that contains the name of the current module. If the module is the main program, __name__ will be set to the string "__main__".
- What does the 'b' character do in front of a string literal?Python
The 'b' character in front of a string literal indicates that the string is a bytes literal.
- What does the "at" (@) symbol do in Python?Python
In Python, the "at" (@) symbol is used to decorate a function.
- What does the "yield" keyword do?Python
Python, the yield keyword is used in the body of a function like a return statement, but instead of returning a value and terminating the function, it yields a value and suspends the function's execution.
- What exactly do "u" and "r" string prefixes do, and what are raw string literals?Python
In Python, the "r" prefix before a string denotes that it is a raw string literal.
- What IDE to use for Python?Python
There are many Integrated Development Environments (IDEs) that you can use for writing, testing, and debugging Python code.
- What is __future__ in Python used for and how/when to use it, and how it worksPython
The __future__ module in Python allows you to enable new language features which are not compatible with the current version of Python.
- What is __init__.py for?Python
__init__.py is a special Python file that is used to indicate that the directory it is present in is a Python package.
- What is __pycache__?Python
__pycache__ is a directory that is created by the Python interpreter when it imports a module.
- What is a clean "pythonic" way to implement multiple constructors?Python
A "pythonic" way to implement multiple constructors in Python is to use the @classmethod decorator.
- What is a cross-platform way to get the home directory?Python
The os.path module in Python provides a cross-platform way to get the home directory.
- What is a mixin and why is it useful?Python
A mixin in Python is a class that is used to add specific functionality to other classes without inheriting from them.
- What is setup.py?Python
setup.py is a Python script used to build and install Python packages.
- What is the best project structure for a Python application?Python
There is no one "best" project structure for a Python application, as it often depends on the specific requirements and goals of the project.
- What is the difference between __str__ and __repr__?Python
__str__ and __repr__ are two special methods in Python classes.
- What is the difference between dict.items() and dict.iteritems() in Python2?Python
In Python 2, dict.items() returns a list of the dictionary's key-value pairs, whereas dict.iteritems() returns an iterator over the dictionary's key-value pairs.
- What is the difference between null=True and blank=True in Django?Python
In Django, null=True and blank=True are both used to specify options for fields in a model.
- What is the difference between old style and new style classes in Python?Python
In Python, classes can be divided into two types: old-style and new-style.
- What is the difference between pip and conda?Python
pip is the package installer for Python.
- What is the difference between Python's list methods append and extend?Python
The append method adds an item to the end of a list.
- What is the difference between range and xrange functions in Python 2.X?Python
In Python 2.X, range and xrange are used to generate a sequence of numbers.
- What is the difference between venv, pyvenv, pyenv, virtualenv, virtualenvwrapper, pipenv, etc?Python
There are many different tools that you can use to create isolated Python environments, each with their own benefits and drawbacks.
- What is the easiest way to remove all packages installed by pip?Python
The easiest way to remove all packages installed by pip is to use the command pip freeze to get a list of all installed packages, and then pipe that list to pip uninstall -y, like this:
- What is the maximum recursion depth in Python, and how to increase it?Python
The maximum recursion depth in Python is typically 1000, although this can vary depending on the operating system and system settings.
- What is the meaning of single and double underscore before an object name?Python
In Python, a single underscore "_" before an object name indicates that the object is meant to be private, meaning that it should not be directly accessed or modified outside of the class that it is defined in.
- What is the naming convention in Python for variable and function?Python
In Python, variable and function names should be lowercase, with words separated by underscores.
- What is the purpose and use of **kwargs?Python
In Python, kwargs is a way to pass a keyworded, variable-length argument list.
- What is the purpose of the `self` parameter? Why is it needed?Python
The self parameter in Python is used to refer to the instance of an object within a class.
- What is the Python 3 equivalent of "python -m SimpleHTTPServer"Python
In Python 3, you can use the http.server module to run a simple HTTP server.
- What is the Python equivalent for a case/switch statement?Python
The Python equivalent for a case/switch statement is the if-elif-else structure.
- What is the quickest way to HTTP GET in Python?Python
Here's a code snippet for making an HTTP GET request using the requests library in Python:
- What is the use of "assert" in Python?Python
In Python, the assert statement is used to check if a certain condition is true, and if it is not true, raise an exception.
- What should I do with "Unexpected indent" in Python?Python
"Unexpected indent" in Python means that the indentation level of a line of code is not what the interpreter was expecting.
- What's the canonical way to check for type in Python?Python
In Python, you can use the isinstance function to check if an object is an instance of a particular type.
- What's the difference between lists and tuples?Python
Lists and tuples are both used to store multiple items in a single variable, but they are different in a few key ways.
- When to use cla(), clf() or close() for clearing a plot in matplotlib?Python
cla() is used to clear the current axis of a plot in matplotlib.
- Which exception should I raise on bad/illegal argument combinations in Python?Python
You can raise the ValueError exception when you encounter bad or illegal argument combinations in Python.
- Which version of Python do I have installed?Python
You can find the version of Python that you have installed by running the following command in your command prompt or terminal:
- Why am I seeing "TypeError: string indices must be integers"?Python
The "TypeError: string indices must be integers" error is raised when you try to access an element of a DataFrame or Series using a string index instead of an integer index.
- Why can't Python parse this JSON data?Python
Without a specific code snippet and the JSON data that is causing issues, it is difficult to determine why Python is unable to parse the data.
- Why do I get the syntax error "SyntaxError: invalid syntax" in a line with perfectly valid syntax?Python
There are several reasons why you might see the SyntaxError: invalid syntax error in a line with apparently valid syntax.
- Why do people write #!/usr/bin/env python on the first line of a Python script?Python
The #!
- Why do Python classes inherit object?Python
In Python 3, all classes automatically inherit from the object class.
- Why does code like `str = str(...)` cause a TypeError, but only the second time?Python
Code like str = str(...) causes a TypeError because it attempts to re-assign the built-in str type to a new value, which is not allowed.
- Why does comparing strings using either '==' or 'is' sometimes produce a different result?Python
When comparing strings using the '==' operator, the comparison is based on the actual characters in the string.
- Why does Python code run faster in a function?Python
Python code can run faster in a function because of something called "Just-In-Time" (JIT) compilation.
- Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3?Python
The range() function generates a sequence of numbers, starting from the first argument, and ending before the second argument.
- Why is it string.join(list) instead of list.join(string)?Python
The join() method is a string method, so it is called on a string object and takes a list of strings as its argument.
- Why is python setup.py saying invalid command 'bdist_wheel' on Travis CI?Python
The error message "invalid command 'bdist_wheel'" occurs when the "bdist_wheel" module is not installed.
- Why use pip over easy_install?Python
Pip is generally preferred over easy_install because it offers a number of features that easy_install does not, including better package management and more user-friendly command options.
- Working with UTF-8 encoding in Python sourcePython
Here is a code snippet that demonstrates how to work with UTF-8 encoding in a Python source file:
- Writing a list to a file with Python, with newlinesPython
Here is a code snippet that demonstrates how to write a list to a file with newlines in Python:
- Writing a pandas DataFrame to CSV filePython
In the above code snippet, the to_csv method is used to write a DataFrame to a CSV file.
- Writing string to a file on a new line every timePython
Here is an example code snippet for writing a string to a file on a new line every time in Python: