Python Variables Explained with Examples

Python Variables are containers for storing data values. Unlike some other programming languages, Python has no command for declaring a variable – a variable is created the moment you first assign a value to it.

Python Variables Assignment

# Creating a variable and assigning a value
message = "Hello, Python!"
number = 42
pi_value = 3.14159

print(message)  # Output: Hello, Python!
print(number)   # Output: 42
print(pi_value) # Output: 3.14159

Python Variables Naming Rules

• Must start with a letter or underscore
• Can only contain letters, numbers, and underscores
• Are case-sensitive (age, Age, and AGE are different variables)

# Valid variable names
my_variable = "valid"
_variable = "also valid"
variable2 = "still valid"

# Invalid variable names (would cause errors)
# 2variable = "invalid"
# my-variable = "invalid"
# my variable = "invalid"

Python Variables Dynamic Typing

Python variables can change type after they’ve been set.

x = 4       # x is an integer
x = "Sally" # x is now a string
print(x)    # Output: Sally

Python Variables Multiple Assignment

# Assigning multiple variables in one line
a, b, c = "Apple", "Banana", "Cherry"
print(a)  # Output: Apple
print(b)  # Output: Banana
print(c)  # Output: Cherry

# Assigning the same value to multiple variables
x = y = z = "Orange"
print(x)  # Output: Orange
print(y)  # Output: Orange
print(z)  # Output: Orange

Python Variables Types

Python has various data types for variables:

# String
name = "Alice"

# Integer
age = 25

# Float
height = 5.9

# Boolean
is_student = True

# List
fruits = ["apple", "banana", "cherry"]

# Tuple
coordinates = (10.0, 20.0)

# Dictionary
person = {"name": "Bob", "age": 30}

# You can check the type with type()
print(type(name))       # Output: <class 'str'>
print(type(age))        # Output: <class 'int'>
print(type(is_student)) # Output: <class 'bool'>

Python Variables Global vs Local

# Global variable
global_var = "I'm global"

def my_function():
    # Local variable
    local_var = "I'm local"
    print(local_var)      # Works fine
    print(global_var)     # Can access global variables
    
my_function()

print(global_var)         # Works fine
# print(local_var)        # Would cause error - local_var not defined here

Python variables are fundamental to Python programming, allowing you to store and manipulate data throughout your code.