Why is my boolean value an instance of int?

Question

x is of type bool. So why does my code have the output True? I am new to Python. What's going on here?

Code:

x = True
print(isinstance(x, int))

Output:

True

@Chris_Rands Is this the appropriate dupe? Equality does not imply subclass-relationships. edit: just noticed that the question body extends beyond the title. — timgeb, Nov 26 '18 at 14:40

timgeb · Accepted Answer · 2018-11-26T14:34:16.033

2

That's because bool is a subclass of int.

Quoting from the Python Data Model:

Booleans (bool)
These represent the truth values False and True. The two objects representing the values False and True are the only Boolean objects. The Boolean type is a subtype of the integer type, and Boolean values behave like the values 0 and 1, respectively, in almost all contexts, the exception being that when converted to a string, the strings "False" or "True" are returned, respectively.

Answer to comment:

Would it also return True if you did isinstance(bool, int)?

No. True and False are instances of bool and therefore instances of the parent class int, but bool itself is not an instance of int. Being a class it's an instance of type and a subclass of int.

>>> isinstance(bool, int)
False
>>> isinstance(bool, type)
True
>>> issubclass(bool, int)
True

edited Nov 26 '18 at 14:34

answered Nov 26 '18 at 14:25

timgeb

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Would it also return True if you did isinstance(bool, int)? – dfundako Nov 26 '18 at 14:30
@dfundako no, see edit. – timgeb Nov 26 '18 at 14:35
thax dfundako..... – aroN Nov 26 '18 at 15:00

score 0 · Answer 2 · answered Nov 26 '18 at 14:29

0

Because booleans are a subtype of integers. See the docs.

answered Nov 26 '18 at 14:29

TaxpayersMoney

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Really doesnt add anything to the answer that was already here. – dfundako Nov 26 '18 at 14:32
Agreed, we must have been posting at the same time. Feel free to delete. – TaxpayersMoney Nov 26 '18 at 15:01

Why is my boolean value an instance of int?

2 Answers2