Snippets
variables

How-to articles, tricks, and solutions about VARIABLES

"No X11 DISPLAY variable" - what does it mean?

"No X11 DISPLAY variable" is an error message that you might see when trying to run a Java program that uses the X Window System to display a graphical user interface (GUI).

java linux variables x11 headless

accessing a variable from another class

To access a variable from another class in Java, you can use the following steps:

java variables

Best way to test for a variable's existence in PHP; isset() is clearly broken

In PHP, the isset() function is used to check if a variable has been set, meaning that it has been declared and is not equal to NULL.

php isset variables

Can't access global variable inside function

In PHP, if you want to access a global variable inside a function, you need to use the "global" keyword.

php variables global-variables scope

Changing a global variable from inside a function PHP

In PHP, global variables can be accessed and modified from within functions using the global keyword.

php function variables global

How can I print variable and string on same line in Python?

You can use the print() function in Python and use the + operator to concatenate a string and a variable.

string python printing variables

How do I check if a variable exists?

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.

python exception variables

How do I put a variable’s value inside a string (interpolate it into the string)?

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.

string python variables

How do you know a variable type in java?

You can use the instanceof operator to determine the type of a variable in Java.

java variables types

How to check if type of a variable is string?

You can use the type() function in Python to check the type of a variable.

string python variables types

1 2 > >>