What is the best way to determine if a Python object is numeric? I'm using the following test
type(o) in [int, long, float, complex]
But I wonder if there is another way.
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Sometimes you do need such explicit tests, but it's nice to avoid them when possible so that you get the full benefits of duck typing.PM 2Ring– PM 2Ring2015-04-21 13:33:07 +00:00Commented Apr 21, 2015 at 13:33
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The canonical duplicate for this question should really be stackoverflow.com/questions/3441358/…joanis– joanis2022-05-02 15:51:19 +00:00Commented May 2, 2022 at 15:51
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2 Answers
The preferred approach is to use numbers.Number, which is
The root of the numeric hierarchy. If you just want to check if an argument x is a number, without caring what kind, use isinstance(x, Number)
as shown below
In [1]: import numbers
In [2]: isinstance(1, numbers.Number)
Out[2]: True
In [3]: isinstance(1.0, numbers.Number)
Out[3]: True
In [4]: isinstance(1j, numbers.Number)
Out[4]: True
Also, type(o) in [int, long, float, complex] can be rewritten as
isinstance(o, (int, long, float, complex))
to make it more robust, as in able to detect subclasses of int, long, float and complex.
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PM 2Ring
And of course
isinstance(o, numbers.Number) is generally superior to isinstance(o, (int, long, float, complex)) since it means that any object which claims to be some kind of number will pass the test.Try the isinstance function.
Return true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual) subclass thereof
Sample Usage
isinstance(o, (int, long, float, complex))
