Boolean Logic: and / or / not

Conditions are booleans: they are either True or False. You can combine them with three words.

• and is true only when both sides are true.
• or is true when at least one side is true.
• not flips a boolean.

logged_in = True
is_admin = False
print(logged_in and is_admin)   # False
print(logged_in or is_admin)    # True
print(not is_admin)             # True

You will often combine these with comparisons. Here a value is "in range" only when both checks pass:

age = 30
allowed = age >= 18 and age <= 65
print(allowed)   # True

Python also lets you chain comparisons, which reads like math. This means exactly the same thing:

age = 30
allowed = 18 <= age <= 65
print(allowed)   # True

Use not to invert a whole check. not (a and b) is true when they are not both true.