What is a Variable?

Think of a variable as a name that refers to a value. Once you assign a value to a variable, you can use the variable's name to access that value throughout your code. This makes your code more readable and manageable.

The Assignment Operator: =

In Python, you create or update a variable using the assignment operator, which is the equals sign (=). The structure is:
variable_name = value

# The variable `count` now stores the number 10
count = 10
print(count)

10

# The variable `message` now stores the text "Hello, Python!"
greeting = "Hello, Python!"
print(greeting)

Hello, Python!

The value on the right side of = is stored in the variable name on the left. Variable names are case-sensitive (e.g., myVariable is different from myvariable).

Data Types and Reassigning Variables

Variables in Python can hold different types of data, such as numbers (integers, floats), text (strings), and more complex structures like lists. Python automatically determines the type of data a variable holds.

You can also change (reassign) the value stored in a variable at any time:

# Initial assignment
score = 100
print(f"Initial score: {score}")

# Update the score
score = 150
print(f"Updated score: {score}")

# Variables can even change type (though be careful!)
score = "No score yet"
print(f"Final score status: {score}")

Initial score: 100
Updated score: 150
Final score status: No score yet

Variables in Action: A Practical Example

Let's look at a slightly more complex example that involves getting input from a user, which is a common task where variables are essential.

# Ask the user for their name
user_name = input("Enter your name: ")

# Store a personalized greeting message
message = "Hello, " + user_name + "! Welcome."
print(message)

# Example with numbers and type conversion
value_as_string = input("Enter your age: ")
age = int(value_as_string) # Convert string to an integer
print(f"You entered {age}. In two years, you will be {age + 2} years old.")

Enter your name: [User types Alice]
Hello, Alice! Welcome.
Enter your age: [User types 30]
You entered 30. In two years, you will be 32 years old.