Keywords in Python

Introduction

In Python, keywords are reserved words that have special meanings and are integral to the language's syntax. These words cannot be used as identifiers such as variable names, function names, or class names. Understanding Python keywords is essential for writing clear and error-free code.

What Are Keywords in Python?

Keywords in Python are predefined words that serve specific purposes in the language's structure. They help define the grammar and structure of Python code. For instance, if, for, and while are used for control flow, while def and class are used for defining functions and classes, respectively.

List of Python Keywords

As of Python 3.11, there are 36 keywords. You can retrieve the current list of keywords using the keyword module:

import keyword
print(keyword.kwlist)

This will output a list like:

['False', 'None', 'True', 'and', 'as', 'assert', 'async', 'await',
 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except',
 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda',
 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield']

Categories of Python Keywords

Python keywords can be grouped based on their functionality:

• Value Keywords: True, False, None
• Operator Keywords: and, or, not, in, is
• Control Flow Keywords: if, else, elif, for, while, break, continue, pass, try, except, finally, raise, assert
• Function and Class Keywords: def, return, lambda, yield, class
• Context Management Keywords: with, as
• Import and Module Keywords: import, from, as
• Scope and Namespace Keywords: global, nonlocal
• Asynchronous Programming Keywords: async, await

Examples of Python Keywords

Here are some examples demonstrating the use of Python keywords:

# Using 'if', 'elif', and 'else'
x = 10
if x > 0:
    print("Positive")
elif x == 0:
    print("Zero")
else:
    print("Negative")

# Defining a function with 'def' and returning a value with 'return'
def greet(name):
    return "Hello, " + name

print(greet("Alice"))

# Using 'for' loop and 'break'
for i in range(5):
    if i == 3:
        break
    print(i)

Conclusion

Understanding and correctly using Python keywords is fundamental to programming in Python. They define the structure and flow of a Python program. Avoid using these reserved words as identifiers to prevent syntax errors and ensure code clarity.