Checking the number of arguments a function takes

[Chirumer]

user_func is a function with either 1 or 2 parameters.
What's the best way to call the function with 2 parameters if it supports it, or call it with 1 parameter if not?

Here is one way I found..

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def caller(user_func):         # user_func has either 1 or 2 parameters       information = 'some information'     extra_information = 'some other information'       if user_func.__code__.co_argcount == 2:             # if function has 2 parameters         user_func(information, extra_information)     else:             # function has 1 parameter         user_func(information)

[deanhystad]

I prefer catching the exception over trying to predict all possible failures.

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try:     user_func(information, extra_information) except TypeError:     user_func(informationn)

[Gribouillis]

1 2	from inspect import signature nparams = len(signature(user_func).parameters)

Finer details can be obtained by examining the information provided by the Parameter objects.

[Chirumer]

Thanks deanhystad and Gribouillis
I found both your suggestions helpful