How to access closed over variables given only the closure function?

Question

In the following example:

def speak(volume):
    def whisper(text):
        print(text.lower() + ('.' * volume))
    def yell(text):
        print (text.upper() + ('!' * volume))
    if volume > 1:
        return yell
    elif volume <= 1:
        return whisper


func = speak(volume=10)
func('hello')
HELLO!!!!!!!!!! # <== obviously `10` is stored in `func` somewhere

Given func, how would I get the "volume"? Is there something within the func namespace which gives the value of 10? I thought perhaps it would be in func.__globals__ or func.__dict__ but it's in neither.

See https://stackoverflow.com/a/14414638/2958070 for usage of the `__closure__` attribute — Ben, Oct 19 '19 at 22:21
the state variables might have been hidden for a reason. maybe it is not such a good idea to try to access them? — Agnishom Chattopadhyay, Oct 21 '19 at 01:51

score 19 · Accepted Answer · answered Oct 19 '19 at 22:21

19

Below (the code below return 10)

func.__closure__[0].cell_contents

answered Oct 19 '19 at 22:21

balderman

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thanks. What is a "cell object"? I've never come across that `type` before? – FI-Info Oct 19 '19 at 22:22
2

You better have a look here: https://gist.github.com/DmitrySoshnikov/700292 – balderman Oct 19 '19 at 22:24

How to access closed over variables given only the closure function?

1 Answers1