How to check if an object is a generator object in python?

Solution 1:

You can use GeneratorType from types:

>>> import types
>>> types.GeneratorType
<class 'generator'>
>>> gen = (i for i in range(10))
>>> isinstance(gen, types.GeneratorType)
True

Solution 2:

You mean generator functions ? use inspect.isgeneratorfunction.

EDIT :

if you want a generator object you can use inspect.isgenerator as pointed out by JAB in his comment.

Solution 3:

I think it is important to make distinction between generator functions and generators (generator function's result):

>>> def generator_function():
...     yield 1
...     yield 2
...
>>> import inspect
>>> inspect.isgeneratorfunction(generator_function)
True

calling generator_function won't yield normal result, it even won't execute any code in the function itself, the result will be special object called generator:

>>> generator = generator_function()
>>> generator
<generator object generator_function at 0x10b3f2b90>

so it is not generator function, but generator:

>>> inspect.isgeneratorfunction(generator)
False

>>> import types
>>> isinstance(generator, types.GeneratorType)
True

and generator function is not generator:

>>> isinstance(generator_function, types.GeneratorType)
False

just for a reference, actual call of function body will happen by consuming generator, e.g.:

>>> list(generator)
[1, 2]

See also In python is there a way to check if a function is a "generator function" before calling it?

Solution 4:

The inspect.isgenerator function is fine if you want to check for pure generators (i.e. objects of class "generator"). However it will return False if you check, for example, a izip iterable. An alternative way for checking for a generalised generator is to use this function:

def isgenerator(iterable):
    return hasattr(iterable,'__iter__') and not hasattr(iterable,'__len__')