Booleans and Comparisons

Why this matters

Every decision a program makes comes down to a question with a yes/no answer: is the password correct? is the cart empty? is it past noon? In Python, yes/no values are called booleans, and you get them by comparing things.

The idea

A comparison produces a bool, which is either True or False:

Operator	Meaning	Example	Result
==	equal to	3 == 3	True
!=	not equal to	3 != 4	True
< >	less / greater than	2 < 1	False
<= >=	at most / at least	5 >= 5	True

Careful: == compares; a single = assigns.

You can store the result like any other value:

age = 15
is_teen = age >= 13 and age <= 19
print(is_teen)       # True

Combine booleans with and, or and not:

Expression	Meaning
a and b	both must be true	True and False → False
a or b	at least one must be true	True or False → True
not a	flips it	not True → False

Python also lets you chain comparisons the way you would in maths: 13 <= age <= 19.

Strings can be compared too: "apple" == "apple" is True, and capital letters matter: "Apple" == "apple" is False.

Try it

Predict each result, then run it: print(5 > 3), print(5 == "5"), print(not (2 < 1)), print(10 % 2 == 0). The last one is a classic way to test whether a number is even.

Your turn

A ride requires riders to be at least 8 years old and at least 120 cm tall. The starter reads an age and a height (in cm).

1. Create a variable can_ride that is True only when both requirements are met.
2. Print can_ride.

For an age of 10 and a height of 130 it prints True.

Recap

• Comparisons (==, !=, <, >, <=, >=) give True or False.
• and, or and not combine or flip booleans.
• Compare with ==; assign with =.

Common mistakes

• Using = instead of == when comparing.
• Quoting booleans: "True" is text, not a boolean.
• Mixing up and and or: at least 8 and at least 120 cm needs both.