How to pass a function with parameters with a function in python?

Question

Consider this:

def function1():
   def nestedfunc(param1, **kw):
      logging.info("nested function %s" % kw) #error
   function2(nestedfunc("is called"), string="not default")


def function2(func, string="default"):
   try:
      #doing some setting
      func()
   finally:
      #reset back to setting

I am getting:

func()
TypeError: 'NoneType' object is not callable

I am assuming the func() is not passing parameters and it causes the error.

To clarify, the desire result is to be able to call func() with any number of parameters added.

Does anyone know what is the proper way to do it? Any advice would be thankful!

the desire result is to be able to call func() with any number of parameters added. — tipsywacky
– tipsywacky, Commented May 24, 2016 at 9:41

Eugene Yarmash · Accepted Answer · 2016-05-24 09:49:17Z

4

Your function2 recieves func=None because that's the (default) return value of nestedfunc(), which is called with the parameter "is called". You could use functools.partial to 'freeze' some function's arguments:

from functools import partial

def function1():
   def nestedfunc(param1, **kw):
      logging.info("nested function %s" % kw) #error
   function2(partial(nestedfunc, "is called"), string="not default")

edited May 24, 2016 at 9:49

answered May 24, 2016 at 9:41

Eugene Yarmash

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1 Comment

user5547025 Over a year ago

Very nice, functool.partial is the right way to go.

user5547025 · Accepted Answer · 2016-05-24 09:39:37Z

1

nestedfunc("is called") is the value returned by the function call: None. You should pass nestedfunc to function2 without calling it first.

If you want to pass a parameter to nestedfunc, pass it to function2 first.

def function1():
   def nestedfunc(param1, **kw):
      logging.info("nested function %s" % kw) #error
   function2(nestedfunc, "is called", string="not default")


def function2(func, funcparam, string="default"):
   try:
      #doing some setting
      func(funcparam)
   finally:
      #reset back to setting

answered May 24, 2016 at 9:39

user5547025

2 Comments

tipsywacky Over a year ago

this is what i did, but my goal is to add the func() with any number of params. not sure if it is possible.

user5547025 Over a year ago

The other answer does what you want.

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