Returning functions

Question

I have functions that use returned variables.

How do I call them in a main function like this:

    text = 'a'
    def a(text):
        text = x
        return x
    
    def b(x):
        x = z
        return z

    def main():
        # What do I put here to call function a and b?
    
    main()

The same thing you put below to call function `main`. But it's not going to work without some reorganisation. — jonrsharpe, Feb 24 '18 at 18:59
Why don't you try it and find out? One obvious problem with that is that you don't have a callable `x` in scope there, but that should be clear from the traceback. — jonrsharpe, Feb 24 '18 at 19:02

score 0 · Answer 1 · answered Mar 05 '18 at 10:31

How do I call them

You already know how to call them ;)

def main():
...
main()

So I assume you are bewildered by:

def a(text):
text = x
return x

That x is not defined in a nor is it passed by argument to it. But that's OK. In python, all variables defined outside function are still visible inside it. Only exception is if argument of function have the same name as one of those variables. Then argument will take precedence.

This mechanism is called closure. Function close over some variable that already exists in scope when function is defined.

You can learn about it some more here: https://www.learnpython.org/en/Closures

score 0 · Answer 2 · edited Jan 13 '19 at 12:44

0

text = 'a'
def a(text):
    text = x
    return x

def b(x):
    x = z
    return z

def main():
    x = a(text)    
    z = b(x)
main()

This might be what you want

edited Jan 13 '19 at 12:44

Bhargav Rao

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answered Jan 13 '19 at 11:16

Andrii Chumakov

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score 0 · Answer 3 · answered Jun 22 '20 at 17:15

It is not clear what are you trying to achieve. You are using variable x in the function a and variable z in function b without defining these two variables.

Moreover, you are setting variable text in function a without capturing it using statement global, look here for more information.

And global variables are considered to be bad practice.

Returning functions

3 Answers3