result[isinstance(item, int)] clear solution for Sum by Type by flpo - python coding challenges

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result[isinstance(item, int)] solution in Clear category for Sum by Type by flpo

def sum_by_types(items):
    result = ['', 0]
    for item in items:
        result[isinstance(item, int)] += item
    return result

March 5, 2020

Comments:

yoichi on March 9, 2020, 8:31 p.m.
Magically, there is no if sentence!

veky on March 12, 2020, 12:55 p.m.
bool is good, but dict is better. See mine. ;-)

Safwan_Samsudeen on Nov. 26, 2020, 2:16 a.m.
I think this is more brilliant and clear if you wrap your head around the fact that booleans are numbers in Python.

veky on Nov. 26, 2020, 5:05 a.m.
Of course bools are ints. But this covers only two possibilities. dict gives you switch, so you can have as many possibilites as you want.

Safwan_Samsudeen on Nov. 26, 2020, 5:21 a.m.
Sorry, I am relatively new to Python. What do you mean dict gives you switch? As for 'of course bools are ints', beginners don't know `0 == True`.

veky on Nov. 27, 2020, 3:46 a.m.
I don't know that 0 == True either. Because it isn't. ;-P Seriously, read about <a href="https://en.wikipedia.org/wiki/Iverson_bracket">Iverson bracket</a>. It is a powerful mathematical concept which has nothing to do with Python. Yes, many people don't know about it, but not because they are beginners in Python. :-) About using the dict as a switch: first, have you seen <a href="https://py.checkio.org/mission/sum-by-type/publications/veky/python-3/put-it-in-neutral/">my solution</a>? I hope that should clear what "as many possibilities as you want" means.

Safwan_Samsudeen on Nov. 27, 2020, 4:13 a.m.
Sorry! `1 == True`

r_tchaik on May 16, 2020, 2:03 p.m.
Great!

krzysztofrrr on May 17, 2020, 9:53 p.m.
Nice and clever. I think it would fit more into creative category :)

Urza on May 27, 2020, 7:16 p.m.
Brilliant.

furtadobb on Sept. 2, 2020, 12:53 p.m.
How does it really work. I did not get it. Also, it did not pass the empty assertion because it checks against a tuple, not a list. Thanks.

furtadobb on Sept. 2, 2020, 1:19 p.m.
Ah! I got it. Using 1 or 0 as an index for the list. Perfect! Really nice.

hvacrua on Sept. 30, 2020, 11:15 a.m.
Nice & clever solution! ^__^

Selindian on Feb. 23, 2022, 10:39 p.m.
Cool way to solve this with bool as index value. I really have learned something. Thank you! But the mission seem to have changed a bit. When checking out your solution I got: <pre class='brush: python'>Traceback (most recent call last): File "12-sum-by-type.py", line 42, in <module> assert sum_by_types([]) == ("", 0) AssertionError </pre> Currently return value has to be "Tuple[str, int]". After changing the "return line" into: <pre class='brush: python'>return tuple(result) </pre> all was good.

asapfrogy on July 31, 2023, 4:04 p.m.
great

List, list and list again

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