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Hectal
Back to the lesson: Topic 1.4 — True, False and None
Python · Example 2 of 3

None, and the function that returns nothing

The word hello is printed by print itself. The None on the next line is what print returned.

A bool is either True or False, the answer to a yes-or-no question. None is Python's way of saying "no value here". Every value also has a truthiness: empty and zero values count as false, nearly everything else as true.

Change the code and press Run (Ctrl+Enter). Predict what will happen first, then break it on purpose and read what changes. Your edits are saved and match the lesson page.

Ready for more? This phase has 6 hands-on exercises with automatic checks.

Practice questions

Write the code in the editor, run it, then open the model answer to compare.

01

Set x = 0 and y = None. Print bool(x) and bool(y), and then x is None and y is None.

02

Set a = 3, b = 0, c = 7 and print how many of them are non-zero by adding up bool() values.

03

Store the result of print("hi") in a variable and print the variable. Say what it shows.

Explain it without notes

01

Which values are falsy in Python? Give at least five.

02

Why should you test x is None and not x == None?

03

What is the relationship between bool and int?

04

Why does bool("False") return True?

None, and the function that returns nothing
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Expected output

None
True
True
<class 'NoneType'>
hello
None
False True False