Get name of outer function from inner function object in python

Question

Assume a nested function in python, where outer denotes the outer function and inner denotes the inner function. The outer function provides parametrization of the inner function and returns an instance of this parametrized function.

I want to obtain the name of the outer function, given an instance of the inner function which is returned by the outer function. The code is as follows:

def outer(a):
    def inner(x):
        return x*a
    return inner
p = outer(3)
print p  # prints inner
print p(3)  # prints 9

How can I print the name of the outer function, ie outer, given only p? Thanks!

You cannot. print p only prints 'inner' because 'outer' returns a function that happens to be 'inner' — Tim
– Tim, Commented Jan 5, 2016 at 15:57
Actually this is not a bad question, if you are looking for why you cannot do it :) — FunkySayu
– FunkySayu, Commented Jan 5, 2016 at 16:07

Vincent Savard · Accepted Answer · 2016-01-05 16:12:57Z

4

You can use functools.wraps:

from functools import wraps

def outer(a):
    @wraps(outer)
    def inner(x):
        return x*a
    return inner
p = outer(3)
print p  # <function outer at ...>

answered Jan 5, 2016 at 16:12

Vincent Savard

36.1k10 gold badges71 silver badges73 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

the_max Over a year ago

Thanks, looks like an elegant solution!

piman314 · Accepted Answer · 2016-01-05 16:15:26Z

0

This is by no means an elegant solution, and I personally wouldn't use it. However it answers the question that you asked.

def outer(a):
    def inner(x):
        return x*a
    inner.__name__ = 'outer'
return inner

print p
<function outer at 0x10eef8e60>

answered Jan 5, 2016 at 16:15

piman314

5,35526 silver badges36 bronze badges

Collectives™ on Stack Overflow

Get name of outer function from inner function object in python

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related