Return value in generator function Python 2

Question

I'm wondering how I can write a generator function that also has the option to return a value. In Python 2, you get the following error message if a generator function tries to return a value. SyntaxError: 'return' with argument inside generator

Is it possible to write a function where I specify if I want to receive a generator or not?

For example:

def f(generator=False):
    if generator:
        yield 3
    else:
        return 3

Why don't you write a wrapper function that calls your generator or standard function? — Aidenhjj, Sep 27 '16 at 21:45
No, you can't write one function that can somehow toggle between being a function or a generator. If you feel you have an answer, *write an answer*. — jonrsharpe, Sep 27 '16 at 21:51
Why is the checking being done inside the 'function'? Do the check for needing a generator in the surrounding code. If you need a generator call a generator. If you need a function, call the functional version. — James McCormac, Sep 27 '16 at 22:02

score 4 · Answer 1 · edited May 23 '17 at 10:27

4

Mandatory reading: Understanding Generators in Python

Key information:

yield anywhere in a function makes it a generator.

Function is marked as generator when code is parsed. Therefore, it's impossible to toggle function behavior (generator / not generator) based on argument passed in runtime.

edited May 23 '17 at 10:27

Community

1
1

answered Sep 27 '16 at 22:01

Łukasz Rogalski

22,092
8
59
93

Return value in generator function Python 2

1 Answers1

Linked