Logical Operators

In this section you’ll learn logical operators—they let you combine two or more conditions into one. You’ve already used comparison operators to build a single condition (e.g. age >= 18). Logical operators are how you say “this condition and that condition” or “this condition or that condition” or “not this condition.”

The three logical operators in Python:

• and — True only when both conditions are true.
• or — True when at least one condition is true.
• not — Flips the result: true becomes false, false becomes true.

The and operator

Use and when you need both conditions to be true. If either one is false, the whole expression is false.

age = 20
has_id = True
 
if age >= 18 and has_id:
    print("You can enter the club!")
else:
    print("Sorry, you cannot enter the club.")

The person can enter only if they are 18 or older and they have an ID. Both must be true.

The or operator

Use or when at least one of the conditions can be true. If either one is true, the whole expression is true.

day = "Saturday"
 
if day == "Saturday" or day == "Sunday":
    print("It's the weekend!")
else:
    print("It's a weekday.")

If the day is Saturday or Sunday, we print the weekend message. Only one of the conditions has to be true.

The not operator

Use not to flip a condition: if it was true, not makes it false, and vice versa.

is_raining = False
 
if not is_raining:
    print("It's a nice day outside!")
else:
    print("Don't forget your umbrella!")

Here, is_raining is False. So not is_raining is True, and we print “It’s a nice day outside!” If is_raining were True, we’d print the umbrella message instead.

Combining logical operators

You can use more than one logical operator in a single condition. Parentheses help make the order clear.

age = 25
has_id = True
is_member = False
 
if (age >= 18 and has_id) or is_member:
    print("You can enter the club!")
else:
    print("Sorry, you cannot enter the club.")

You can enter if (you’re 18+ and have an ID) or if you’re a member. The parentheses show that we check “18+ and has ID” first, then we allow members with the or.