Python Get Started

This page walks you through everything you need to go from zero to a working Python program. You will install Python, run it interactively, write a script, and explore the five core building blocks every Python program relies on: variables and data types, operators, control structures, and functions.

If you have not read the language overview yet, start with Python Intro.

Installing Python

Python is free and open-source. Download the installer for your operating system from python.org.

Verify the installation

Open a terminal (Command Prompt on Windows, Terminal on macOS/Linux) and run:

python3 --version

You should see output like Python 3.12.0. On Windows the command may be python instead of python3.

The interactive shell (REPL)

Python ships with an interactive shell — a Read-Eval-Print Loop (REPL) — that lets you type expressions and see results immediately. It is perfect for experimenting:

$ python3
Python 3.12.0 (...)
>>> 2 + 3
5
>>> 10 / 3
3.3333333333333335
>>> type(42)
<class 'int'>
>>> type('hello')
<class 'str'>
>>> exit()

Type exit() or press Ctrl+D (Ctrl+Z then Enter on Windows) to quit the REPL.

Choosing an editor or IDE

For anything beyond quick experiments, write your code in a file. Popular choices:

• VS Code with the Python extension — the most-used free option.
• PyCharm Community — a full-featured Python IDE.
• IDLE — bundled with Python; minimal but always available.

Writing Your First Python Program

Create a new file called hello.py in any folder, and type:

print("Hello, World!")

Save the file, then run it from the terminal:

python3 hello.py

Expected output:

Hello, World!

print() is a built-in function that writes text to the console. The string "Hello, World!" is the argument you pass to it.

Variables and Data Types

A variable is a named container for a value. You create one by writing a name, the = sign, and a value — no type declaration needed:

my_age = 30           # int   — whole numbers
my_weight = 65.5      # float — decimal numbers
my_name = "Alice"     # str   — text
is_python_fun = True  # bool  — True or False

print(my_age)         # 30
print(my_name)        # Alice
print(is_python_fun)  # True

print(type(my_age))   # <class 'int'>
print(type(my_name))  # <class 'str'>

Python infers the type from the value you assign. You can confirm the type of any value with the built-in type() function.

F-strings: embedding variables in text

The clearest way to build strings that contain variable values is an f-string (available since Python 3.6). Prefix the string with f and wrap expressions in curly braces:

name = "Alice"
age = 30
print(f"My name is {name} and I am {age} years old.")
# My name is Alice and I am 30 years old.

A first look at lists

Python also has lists — ordered collections of values. You will explore them in depth later, but they appear in almost every beginner program:

fruits = ["apple", "banana", "cherry"]
print(fruits[0])   # apple   (indexes start at 0)
print(len(fruits)) # 3

For a full breakdown of all built-in types, see Python Data Types.

Operators

Operators let you compute new values from existing ones. Python groups them by purpose:

Arithmetic operators

x = 10
y = 3

print(x + y)   # 13  — addition
print(x - y)   # 7   — subtraction
print(x * y)   # 30  — multiplication
print(x / y)   # 3.3333333333333335 — true division (always float)
print(x // y)  # 3   — floor division (rounds down to int)
print(x % y)   # 1   — modulus (remainder)
print(x ** y)  # 1000 — exponentiation

Notice the difference between / (true division, always produces a float) and // (floor division, discards the remainder).

Comparison operators

Comparison operators return True or False:

a = 10
b = 20

print(a == b)   # False — equal to
print(a != b)   # True  — not equal to
print(a > b)    # False — greater than
print(a < b)    # True  — less than
print(a >= b)   # False — greater than or equal to
print(a <= b)   # True  — less than or equal to

Logical operators

p = True
q = False

print(p and q)  # False — both must be True
print(p or q)   # True  — at least one must be True
print(not p)    # False — inverts the value

See Python Operators for bitwise, assignment, and identity operators.

Control Structures

Control structures decide which code runs and how many times it runs.

If / elif / else

temperature = 25

if temperature > 30:
    print("hot")
elif temperature > 20:
    print("warm")   # prints this — 25 > 20
else:
    print("cool")

Python checks each condition in order and runs the first block that is True. The elif and else branches are optional.

For loops

A for loop iterates over any sequence — a list, a string, or a range:

# Loop over a list
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit)
# apple
# banana
# cherry

# Loop a fixed number of times with range()
for i in range(1, 6):
    print(i)
# 1  2  3  4  5

range(start, stop) generates integers from start up to (but not including) stop.

While loops

A while loop repeats as long as its condition is True:

count = 0
while count < 3:
    print("count:", count)
    count += 1
# count: 0
# count: 1
# count: 2

Always make sure the condition eventually becomes False, or the loop runs forever.

For deeper coverage of loops, see Python For Loops and Python While Loops.

Functions

A function is a named, reusable block of code. You define it once with def and call it as many times as you like:

def greet(name):
    return f"Hello, {name}!"

print(greet("World"))   # Hello, World!
print(greet("Alice"))   # Hello, Alice!

Functions can have default parameter values, which are used when the caller does not supply that argument:

def power(base, exponent=2):
    return base ** exponent

print(power(3))     # 9  — exponent defaults to 2
print(power(3, 3))  # 27 — caller supplies exponent

The if __name__ == "__main__" guard

When Python runs a .py file directly, it sets the special variable __name__ to "__main__". When the file is imported by another module, __name__ is the file's name instead. Wrapping your startup code in this guard prevents it from running on import:

def greet(name):
    return f"Hello, {name}!"

if __name__ == "__main__":
    print(greet("World"))

This is a best practice for any script you also plan to import as a module.

For more on functions, see Python Functions.

Installing Packages with pip

Python's package manager, pip, lets you add thousands of third-party libraries. For example, to install the popular requests library for making HTTP calls:

pip3 install requests

After installation, import and use it in your code:

import requests

response = requests.get("https://api.github.com")
print(response.status_code)   # 200

Run pip3 list to see all installed packages, and pip3 install --upgrade <package> to update one.

What to Learn Next

You now have Python installed and understand the five essential building blocks. Good next steps:

• Python Syntax — indentation rules, comments, and line continuation in detail.
• Python Variables — naming rules, multiple assignment, and variable deletion.
• Python Data Types — strings, numbers, lists, tuples, dicts, sets, and booleans in depth.
• Python Comments — single-line and multi-line comments, docstrings.
• Python Operators — the complete operator reference.

Practice