return vs. print in nested function example

[Mark17]

Here's a nested function:

def outer():
    n = 1
    
    def inner():
        n = 2
        print(n)
        #return n
    
    inner()
    return n

If I type outer(), then I get 2 and 1 on separate lines. If I comment out Line 6 instead of 7, then I only get 1 as a single line of output.

Why is this? In the latter case, inner() should return n (2) and inner() is called in the outer function.

[bowlofred]

This is similar to your other question. In interactive mode, the result of an expression is printed. But that does not happen by default. Normally bare expressions are evaluated, but any result is just discarded unless printed or assigned. You may want to try running programs from files, not from the interactive prompt.

Yes inner() does evaluate to 2, but that value is not used. Then outer() evaluates to 1. Since you typed it, the interactive shell prints that result for you.

[Mark17]

This is similar to your other question. In interactive mode, the result of an expression is printed. But that does not happen by default. Normally bare expressions are evaluated, but any result is just discarded unless printed or assigned. You may want to try running programs from files, not from the interactive prompt.

Yes inner() does evaluate to 2, but that value is not used. Then outer() evaluates to 1. Since you typed it, the interactive shell prints that result for you.

Sorry for the duplication. I guess it's because I'm still confused.

Jupyter Notebook is 100% interactive, correct? I want to continue using it as I've found it very helpful and heard a lot of good things. This seems to be a limitation, though, because it prevents me from seeing the results of true Python (for lack of a better term)?

[bowlofred]

Interactive sessions give you a way to view intermediate calculations and expressions. They shouldn't change the result of the program, but they might display some of the data differently.

If you want to view the result from inner(), you can just print() it.

def outer():
    n = 1

    def inner():
        n = 2
        #print(n)
        return n

    print(inner()) #prints the result of inner() or a "2"
    return n

outer() # evaluates to 1, but isn't printed

[jefsummers]

It's just learning the rules of Jupyter.
Make your cell breaks in logical places, where you would like to see the interval result (but not in the middle of a function).
Recognize Jupyter will display the output of the last expression, IF NOT ASSIGNED.

dfA = df

No display

dfA

Dataframe A will be displayed, according to your display rules