Why does 'if not ' check empty string in python

Question

Hi I have a quick question regarding 'if not ..' in py.

This is a function that should take a list of strings and return a string.

I wondered what does the first line(if not strs) do? I guess it checks if the input list strs is empty or not? How does it work? Doesn't 'if not' check if it is opposite of expected value, like 'if not None'? Thank you!

def longestPrefix(strs):

        # Empty list
        if not strs: return ""
         ....

AlyM.Aly · Answer 1 · 2019-07-24T09:49:04.653

1

Empty strings are False in Boolean context, therefore if not False is True

edited Jul 24 '19 at 09:49

answered Jul 24 '19 at 05:13

AlyM.Aly

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Ummmm, `not [False]` is `False`. – Stephen Rauch Jul 24 '19 at 05:18
@StephenRauch sorry man i will edit that, i meant the brackets as place holders, like if not False is True , but i wanted to show that the False is the empty string – AlyM.Aly Jul 24 '19 at 05:24

Why does 'if not ' check empty string in python

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