Introduction

Keywords in Python are reserved words that have special meanings and purposes within the language. They serve as the foundation for defining syntax rules and structures in Python programs. In this article, we'll explore all the keywords used in Python, along with examples demonstrating their usage and output.

Python Keywords

Python has a total of 35 keywords as of Python 3.9. These keywords are case-sensitive and cannot be used as identifiers (variable names, function names, etc.) in Python programs. Here's a list of all the keywords in Python:

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

Examples of Python Keywords

Let's explore each Python keyword with examples demonstrating their usage:

1. False, True, and None

These keywords represent the Boolean values False, True, and None, respectively.

print(False)
print(True)
print(None)

Output:

False
True
None

2. if, else, and elif

These keywords are used for conditional statements.

x = 5

if x > 0:
    print("Positive")
elif x == 0:
    print("Zero")
else:
    print("Negative")

Output:

Positive

3. for and while

These keywords are used for loop constructs.

# Using for loop
for i in range(5):
    print(i)

# Using while loop
count = 0
while count < 5:
    print(count)
    count += 1

Output:

0
1
2
3
4
0
1
2
3
4

4. def and return

These keywords are used for defining functions and returning values from functions.

# Function definition
def add(a, b):
    return a + b

# Function call
result = add(3, 4)
print(result)

Output:

7

5. class, pass, and del

These keywords are used for defining classes, placeholder statements, and deleting objects, respectively.

# Class definition
class MyClass:
    pass

# Object creation
obj = MyClass()

# Deleting object
del obj

6. try, except, and finally

These keywords are used for exception handling.

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Error: Division by zero")
finally:
    print("Cleanup code")

Output:

Error: Division by zero
Cleanup code

7. assert

This keyword is used for debugging purposes to ensure that a given condition is true.

x = 5
assert x > 0, "Value must be positive"
print("Assertion passed")

Output:

Assertion passed

8. with

This keyword is used for resource management and ensures that a context manager's __enter__() and __exit__() methods are properly invoked.

with open("example.txt", "w") as file:
    file.write("Hello, Python!")

9. async and await

These keywords are used for asynchronous programming in Python.

import asyncio

async def greet():
    print("Hello")
    await asyncio.sleep(1)
    print("World")

asyncio.run(greet())

Output:

Hello
World

10. import

The import keyword is used to import modules or specific objects from modules in Python.

# Importing the math module
import math

# Using a function from the math module
print(math.sqrt(25))

Output:

5.0

11. break

The break keyword is used to exit from the nearest enclosing loop (for, while, or do-while) prematurely.

# Using break in a loop
for i in range(10):
    if i == 5:
        break
    print(i)

Output:

0
1
2
3
4

12. in

The in keyword is used to check if a value exists in a sequence (list, tuple, string, etc.).

# Using in to check membership in a list
my_list = [1, 2, 3, 4, 5]
print(3 in my_list)

Output:

True

13. raise

The raise keyword is used to raise exceptions explicitly in Python.

# Using raise to raise an exception
x = -1
if x < 0:
    raise ValueError("Value must be positive")

Output:

ValueError: Value must be positive

14. is

The is keyword is used for identity comparison, checking if two objects refer to the same memory location.

# Using is for identity comparison
x = [1, 2, 3]
y = x
print(x is y)

Output:

True

15. and

The and keyword is used for logical conjunction, evaluating to True if both conditions are True.

# Using and for logical conjunction
x = 5
print(x > 0 and x < 10)

Output:

True

16. continue

The continue keyword is used to skip the rest of the code inside a loop and continue with the next iteration.

# Using continue in a loop
for i in range(5):
    if i == 2:
        continue
    print(i)

Output:

0
1
3
4

17. lambda

The lambda keyword is used to create anonymous functions (functions without a name).

# Using lambda to create an anonymous function
add = lambda x, y: x + y
print(add(3, 4))

Output:

7

18. as

The as keyword is used for aliasing when importing modules or referencing class names.

# Using as for aliasing
import math as m
print(m.sqrt(25))

Output:

5.0

19. from

The from keyword is used with import to import specific objects from modules.

# Using from to import specific objects
from math import sqrt
print(sqrt(25))

Output:

5.0

20. nonlocal

The nonlocal keyword is used to declare non-local variables in nested function scopes.

# Using nonlocal to modify a variable in a nested function
def outer():
    x = 5
    def inner():
        nonlocal x
        x = 10
    inner()
    print(x)

outer()

Output:

10

21. global

The global keyword is used to declare global variables inside functions.

# Using global to modify a global variable inside a function
x = 5
def modify_global():
    global x
    x = 10

modify_global()
print(x)

Output:

10

22. not

The not keyword is used for logical negation, evaluating to True if the condition is False.

# Using not for logical negation
x = 5
print(not x > 10)

Output:

True

23. or

The or keyword is used for logical disjunction, evaluating to True if at least one condition is True.

# Using or for logical disjunction
x = 5
print(x > 10

 or x < 0)

Output:

False

24. yield

The yield keyword is used in generator functions to produce a series of values.

# Using yield to create a generator function
def my_generator():
    yield 1
    yield 2
    yield 3

gen = my_generator()
print(next(gen))
print(next(gen))
print(next(gen))

Output:

1
2
3

Conclusion

Keywords are an integral part of Python's syntax and are used to define the structure and behavior of Python programs. Understanding and mastering these keywords is essential for becoming proficient in Python programming. By exploring the examples provided in this article, you'll gain a deeper understanding of how each keyword is used and its significance in Python programming. Experiment with these keywords in your own Python projects to enhance your programming skills and build robust applications.