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Testing the data type of a value


Luuk <luuk at invalid.lan> writes:

> On 12-5-2019 16:07, Piet van Oostrum wrote:
>> Luuk <luuk at invalid.lan> writes:
>>
>>> After thinking about this, (i am prettry new to python), i was doing this:
>>>
>>>>>> print(type(5),type(int),type(5)==type(int),type(5)==int)
>>> <class 'int'> <class 'type'> False True
>>>
>>> Can someone explain why   type(5)==int   evaluates to   True ?
>>>
>>>>> print(int)
>> <class 'int'>
>>
>> The value of int is the class int, which is the class of 5, so type(5) is also that same class int.
>
>
> Maybe i should have asked this:
>
> What is the difference between 'type(5)==int'? and 'isinstance(5,int)'
>
> and, if there is no difference why did someone invent 'isinstance()' ...
>

You'll get different behaviour when subclassing is involved.

https://docs.python.org/3/library/functions.html#isinstance

    isinstance(object, classinfo)

    Return true if the object argument is an instance of the classinfo
    argument, or of a (direct, indirect or virtual) subclass thereof.

-- 
regards,
kushal