Control FlowLesson 5 of 1912 min
Booleans and Comparisons
Ask yes/no questions about your data and combine the answers with and, or, and not.
By the end you will be able to
- Compare values with ==, !=, <, >, <=, >=
- Combine conditions using and, or, not
- Predict which values Python treats as falsy
Every decision a program makes comes down to a bool: True or False. Comparison operators produce them.
Python
Output
True
False
True
False
True
— expected output; press Run to execute it yourselfCombining conditions
and— True only when both sides are Trueor— True when at least one side is Truenot— flips a bool
Python
Output
True
False
False
True
— expected output; press Run to execute it yourselfTruthiness
Any value can be used where a bool is expected. Python treats a small, memorable set of values as falsy; everything else is truthy.
Falsy: False, 0, 0.0, "" (empty string), [] (empty list), {} (empty dict), None.
This is why if items: reads so naturally — it means "if there are any items".
Python
Output
False True
False True
False True
False
Name is missing
— expected output; press Run to execute it yourselfExercise
Write a function can_vote(age, is_citizen) that returns True only when the person is at least 18 and a citizen.
Python
Output
Press Run to execute this code.
Check your understanding
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