Why does 'if not ' check empty string in python [duplicate]

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 · Accepted Answer · 2019-07-24 09:49:04Z

1

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

edited Jul 24, 2019 at 9:49

answered Jul 24, 2019 at 5:13

AlyM.Aly

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2 Comments

Stephen Rauch Over a year ago

Ummmm, not [False] is False.

AlyM.Aly Over a year ago

@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

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