Python Keywords

What You'll Learn: In this tutorial, you'll discover various essential keywords used in Python programming. These keywords help you write conditional statements, loops, and handle errors in your programs.

Key Python Keywords

and
- Description: A logical operator used to combine conditional statements.
- Example:
  python
  if a > 0 and b > 0: print("Both a and b are positive")
as
- Description: Used to create an alias.
- Example:
  python
  import math as m print(m.sqrt(16)) # Output: 4.0
assert
- Description: Used for debugging.
- Example:
  python
  assert x > 0, "x should be greater than 0"

break

Description: Used to break out of a loop.

Example:

python

for i in range(10):
    if i == 5:
        break
    print(i)

class
- Description: Used to define a class.
- Example:
  python
  class MyClass: x = 5
continue
- Description: Used to continue to the next iteration of a loop.
- Example:
  python
  for i in range(10): if i % 2 == 0: continue print(i)

def

Description: Used to define a function.

Example:

python

def my_function():
    print("Hello from a function")

del

Description: Used to delete an object.

Example:

python

my_list = [1, 2, 3]
del my_list[0]
print(my_list)  # Output: [2, 3]

elif

Description: Used in conditional statements, same as else if.

Example:

python

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

else

Description: Used in conditional statements.

Example:

python

if x < 0:
    print("Negative")
else:
    print("Non-negative")

except
- Description: Used with exceptions, to specify what to do when an exception occurs.
- Example:
  python
  try: print(10 / 0) except ZeroDivisionError: print("You can't divide by zero!")
False
- Description: Boolean value, result of comparison operations.
- Example:
  python
  print(False) # Output: False

finally

Description: Used with exceptions, a block of code that will be executed no matter if there is an exception or not.

Example:

python

try:
    print(10 / 0)
except ZeroDivisionError:
    print("You can't divide by zero!")
finally:
    print("This code runs no matter what")

for
- Description: Used to create a for loop.
- Example:
  python
  for i in range(5): print(i)
from
- Description: Used to import specific parts of a module.
- Example:
  python
  from math import sqrt print(sqrt(16)) # Output: 4.0
global
- Description: Used to declare a global variable.
- Example:
  python
  def my_function(): global x x = 10
if
- Description: Used to make a conditional statement.
- Example:
  python
  if x > 0: print("Positive")
import
- Description: Used to import a module.
- Example:
  python
  import math print(math.sqrt(16)) # Output: 4.0
in
- Description: Used to check if a value is present in a list, tuple, etc.
- Example:
  python
  if 3 in [1, 2, 3]: print("3 is in the list")
is
- Description: Used to test if two variables are equal.
- Example:
  python
  a = [1, 2, 3] b = a print(a is b) # Output: True
lambda
- Description: Used to create an anonymous function.
- Example:
  python
  x = lambda a: a + 10 print(x(5)) # Output: 15
None
- Description: Represents a null value.
- Example:
  python
  x = None print(x) # Output: None

nonlocal

Description: Used to declare a non-local variable.

Example:

python

def outer():
    x = "local"
    def inner():
        nonlocal x
        x = "nonlocal"
        print("inner:", x)
    inner()
    print("outer:", x)

not
- Description: A logical operator.
- Example:
  python
  print(not True) # Output: False

or

Description: A logical operator.

Example:

python

if a > 0 or b > 0:
    print("At least one is positive")

pass
- Description: A null statement, a statement that will do nothing.
- Example:
  python
  if x > 0: pass
raise
- Description: Used to raise an exception.
- Example:
  python
  raise ValueError("A custom error message")
return
- Description: Used to exit a function and return a value.
- Example:
  python
  def add(a, b): return a + b
True
- Description: Boolean value, result of comparison operations.
- Example:
  python
  print(True) # Output: True

try

Description: Used to make a try...except statement.

Example:

python

try:
    print(10 / 0)
except ZeroDivisionError:
    print("You can't divide by zero!")

while
- Description: Used to create a while loop.
- Example:
  python
  i = 1 while i < 6: print(i) i += 1
with
- Description: Used to simplify exception handling.
- Example:
  python
  with open('file.txt', 'r') as file: content = file.read()
yield
- Description: Used to return a list of values from a generator.
- Example:
  python
  def generator(): yield 1 yield 2 yield 3

Try It Yourself: Fun Exercises

Conditional Statements and Loops:
- Write a Python program that uses if, elif, else, for, and while to control the flow of your program.
Exception Handling:
- Experiment with try, except, finally, and raise to handle and raise exceptions in your program.
Function and Class Definitions:
- Use def to define functions and class to define classes in a small project.

Summary:

In this Python tutorial, we explored various essential keywords used in Python programming. Understanding these keywords helps you write conditional statements, loops, handle errors, and more. Keep experimenting and have fun with Python!