Boolean Logic

The language of True and False

At its absolute core, a computer only understands two concepts: On and Off, 1 and 0, True and False.

In Python, this is represented by the Boolean data type, which has only two possible values: True and False. (Note the capital letters!).

Comparison Operators

You usually generate Booleans by comparing things.

• == means "is equal to"
• != means "is not equal to"
• > means "is greater than"
• < means "is less than"
• >= means "is greater than or equal to"
• <= means "is less than or equal to"

python
print(5 > 3)   # Output: True
print(10 == 2) # Output: False
print("cat" == "dog") # Output: False

💡 Warning: Be careful not to mix up = (assignment) with == (comparison). One = puts a value into a variable. Two == asks a question: "Are these equal?"

Logical Operators

Sometimes you need to combine multiple questions. Python uses plain English words for this: and, or, and not.

The and operator

Both sides must be True.

python
is_weekend = True
is_sunny = True
print(is_weekend and is_sunny) # Output: True

The or operator

Only one side needs to be True.

python
has_cash = False
has_credit_card = True
print(has_cash or has_credit_card) # Output: True

The not operator

Flips the Boolean to its opposite.

python
is_raining = True
print(not is_raining) # Output: False

What this lesson should give you

After this lesson, you should understand how to:

• identify the two boolean values True and False
• use comparison operators (>, <, ==, !=)
• combine conditions using and and or
• flip logic using not