python dict key iteration for loop and comprehension gives different result

Question

iterating dict keys in a for loop gives (correctly or as desired):

>>> for ky in myDict.keys():
...     print(ky)
...
a1
a2
a3
a4
a5
a6

Whereas -- putting in a comprehension gives -- why the list of None??:

>>> [print(ky) for ky in myDict.keys()]
a1
a2
a3
a4
a5
a6
[None, None, None, None, None, None]

`print()` prints its arguments and returns `None`. What do you expect to be in the list? — Barmar, Nov 21 '21 at 14:38
thank you -- newbie error on my part -- didn't know print had a return value — bhall, Nov 21 '21 at 14:57
In Python every function has a return value: if a function has no return statement, it returns `None`. — joanis, Nov 21 '21 at 18:01

score -2 · Answer 1 · edited Nov 22 '21 at 03:17

-2

print is a function that has None as a return value.

edited Nov 22 '21 at 03:17

Gino Mempin

answered Nov 21 '21 at 14:38

phi friday

1 Answers1