Unable to understand python nested functions

Question

Im trying to figure out how this code prints 5 7 as output. Im unable to understand how this code actually executes.

Code:

def outer_function(x):
    def inner_increment(x):
        return x + 2
    y = inner_increment(x)
    print(x,y)
outer_function(5)

Output:

5 7

This question would be a little more interesting if inner_increment was defined as def inner_increment(): and using x from the scope of outer_function. As it stands, inner_increment is declaring it's own variable x which masks the parameter from outer_function, using none of the scope from outer_function. Because there is no dependency on the scope of outer_function, there is no reason that inner_increment could not just be defined as another top level function. — flakes
– flakes, Commented Sep 16, 2020 at 6:08

javadr · Accepted Answer · 2020-09-16 05:36:49Z

3

It's so simple. As you know statements run sequentially, so the followings will happen:

1- inner_increment will be defined

2- y = inner_increment(x) called, so it passes 5 to the innter_increment function and get 7 as a result putting in y variable.

3- finally it will print 5 and 7 in the output.

answered Sep 16, 2020 at 5:36

javadr

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