Understanding the "and" operator - Why is "None and None" not False?

Question

I though I understood Python the "and" operator. But after seeing

assert (None and None) is None

it was apparently that my understanding was not precise. Which was that None and None would be the same as bool(None) and bool(None).

Does anybody have definition of the "and" operator and can explain the logic.

Does this answer your question? [Python's Logical Operator AND](https://stackoverflow.com/questions/18195322/pythons-logical-operator-and) — Shadowcoder, Jan 15 '21 at 09:52
"Does anybody have definition" - Yes, the documentation does. Why did you not read it? — superb rain, Jan 15 '21 at 09:53

score 2 · Answer 1 · answered Jan 15 '21 at 09:50

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and returns the first value if it is "falsey"*. Otherwise it returns the second one.

For example:

3 and 6 -> 6
0 and 7 -> 0
[] and 'abc' -> []

* a thing is falsey if bool(thing) is False

answered Jan 15 '21 at 09:50

zvone

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score 2 · Accepted Answer · answered Jan 15 '21 at 09:58

2

According to the official documentation:

help('and')

[...] The expression "x and y" first evaluates x; if x is false, its value is returned; otherwise, y is evaluated and the resulting value is returned. [...]

answered Jan 15 '21 at 09:58

asmartin

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Understanding the "and" operator - Why is "None and None" not False?

2 Answers2