Vivienne Reay

Variables

Creating a variable

Pick a name and give it a value:

name = "Alice"
age = 30

Using a variable

Use it anywhere in your code:

print(name)      # Shows Alice
print(age + 5)   # Shows 35

Changing a variable

Assign a new value to replace the old one:

age = 30
age = 31         # The old value (30) is forgotten

Good variable names

Your names should make sense:

• Start with a letter or underscore
• No numbers at the start
• No spaces
• Should describe what's inside

first_name = "Sam"      # Good
total_score = 42        # Good
x = 10                  # Bad - doesn't describe anything

Dynamic typing

Python figures out the type as you go. You can change what type a variable holds:

value = 10        # This is a number
value = "hello"   # Now it's text