Negative form of isinstance() in Python

问题

How would I use a negative form of Python's isinstance()?

Normally negation would work something like

x != 1

if x not in y

if not a

I just haven't seen an example with isinstance(), so I'd like to know if there's a correct way to used negation with isinstance().

回答1:

Just use not. isinstance just returns a bool, which you can not like any other.

回答2:

That would seem strange, but:

if not isinstance(...):
   ...

The isinstance function returns a boolean value. That means that you can negate it (or make any other logical operations like or or and).

Example:

>>> a="str"
>>> isinstance(a, str)
True
>>> not isinstance(a, str)
False

回答3:

Just use not, e.g.,

if not isinstance(someVariable, str):
     ....

You are simply negating the "truth value" (ie Boolean) that isinstance is returning.

来源：https://stackoverflow.com/questions/11748671/negative-form-of-isinstance-in-python