How do I use a Boolean in Python?


Question

Does Python actually contain a Boolean value? I know that you can do:

checker = 1
if checker:
    #dostuff

But I'm quite pedantic and enjoy seeing booleans in Java. For instance:

Boolean checker;
if (someDecision)
{
    checker = true;
}
if(checker)
{
    //some stuff
}

Is there such a thing as a Boolean in Python? I can't seem to find anything like it in the documentation.

1
102
3/16/2018 6:12:23 PM

Accepted Answer

checker = None  # not necessary

if some_decision:
    checker = True

if checker:
    # some stuff

[Edit]

For more information: http://docs.python.org/library/functions.html#bool

Your code works too, since 1 is converted to True when necessary. Actually Python didn't have a boolean type for a long time (as in old C), and some programmers still use integers instead of booleans.

134
7/10/2019 8:50:19 PM

The boolean builtins are capitalized: True and False.

Note also that you can do checker = bool(some_decision) as a bit of shorthand -- bool will only ever return True or False.

It's good to know for future reference that classes defining __nonzero__ or __len__ will be True or False depending on the result of those functions, but virtually every other object's boolean result will be True (except for the None object, empty sequences, and numeric zeros).


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