Multiple return values, just one 'if' checking functions return

Question

What return value(s) does Python check when a function returns multiple values, but there is only one 'if' checking the function's result?

Thank you for your time.

def func1(args):
    return pass, data

def func2
   if func1(args):
       ...
   else 
       raise Exception ...

Besides what @yudhiesh correctly stated, when you return multiple values, Python interprets it as a tuple. So it will be True whenever a tuple would evaluate as True. If a tuple has elements, it will evaluate as True. — MatBBastos
– MatBBastos, Commented Oct 15, 2021 at 13:45
You aren't actually returning multiple values; you're returning a tuple, which happens to contain two values. A tuple is "truthy" if it has a non-zero number of elements, the values of those elements are not relevant. — jasonharper
– jasonharper, Commented Oct 15, 2021 at 13:46
If you're returning two values then it's a tuple of length 2, which is truthy, because nonempty things are truthy. (NB they don't "evaluate to True" as several people are saying.) — khelwood
– khelwood, Commented Oct 15, 2021 at 13:46

Jussi Nurminen · Accepted Answer · 2021-10-15 13:46:26Z

5

return a, b would return a tuple. The if statement will always evaluate, since non-empty tuples evaluate to True.

answered Oct 15, 2021 at 13:46

Jussi Nurminen

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Comments

score 3 · Accepted Answer · 2021-10-15 18:59:42Z

3

When you return multiple values, you're actually returning a tuple containing each of those values.

Your if test will return True regardless of the values (even if they are both None)

answered Oct 15, 2021 at 13:46

user2668284

Thanks. Would the if be true if func1 returned '()', an empty tuple? It does not in the test code I ran.

No. An empty tuple, list, dictionary or string would return False