CODEWITHSUNDEEP
pythonpython-3.x
user38283
user38283

Reputation: 21

How do I in Python not evaluate 0 or 1 as True or False

I have a list:

[2, 5, True, 1, 0, 4, False, False, True]

How do I make 1 and 0 show up as 1 and 0 as opposed to True and False? I'm trying to do:

[True if X == True else False for X in list]

Desired result is:

[False, False, True, False, False, False, False, False, True]

Upvotes: 0

Views: 508

Answers (3)

PirateNinjas
PirateNinjas

Reputation: 2086

This happens because 1 and 0 are "truthy" and "falsey" respectively. You can get around it by using is which uses the underlying singletons for True and False:

[True if X is True else False for X in list]

Edit: as noted in the comments, it's actually more correct to say that True is "1-like" and False "0-like" in some sense because of the underlying implementation. Less catchy than truthy & falsey though!

Upvotes: 1

Mohamed Bahaa
Mohamed Bahaa

Reputation: 11

You need to check the Type of the element by isinstance(X, bool)

So your code will be like this

[True if X == True and isinstance(X, bool)  else False for X in list]

Upvotes: 0

trincot
trincot

Reputation: 350310

You can add a type check:

[isinstance(X, bool) and X for X in list]

NB: the type check should come first, to ensure the expression always evaluates to a boolean.

Upvotes: 1

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