Booleans and comparisons

True and False

A boolean is a value with only two possibilities: True or False. Both are capitalised, and neither takes quotes — "True" is a piece of text, which is a different thing entirely.

Comparisons produce booleans:

7 > 3        # True
7 == 3       # False
"a" == "a"   # True

The single most common beginner bug in any language is writing = where == was meant. = assigns; == asks.

Your turn: set is_adult to whether age is at least 18, and is_teenager to whether age is between 13 and 19 inclusive. Compare — do not just write True or False.

Truthiness

Anything can be used where Python expects a boolean, and it has firm opinions about what counts as false:

• 0, 0.0, "" (empty string), [] (empty list) and None are falsy
• everything else is truthy

So if name: reads as "if name is not empty", which is idiomatic Python and much nicer than if len(name) > 0:.

bool(value) shows you which way a value falls.

Your turn: set has_name to whether name is non-empty, and has_items to whether basket is non-empty — using bool() rather than comparing to "" or 0.