[Tutor] Update values in python dicts

[Alan Gauld]

On 03/05/2021 17:42, Manprit Singh wrote:

> dic = {"A": 1, "B": 8, "H": 5, "L": 4, "K": 7}
> dic.update((x, y+2) for x, y in dic.items() if y%2 != 0)

> dic = {"A": 1, "B": 8, "H": 5, "L": 4, "K": 7}
> for key, val in dic.items():
>     if val%2 != 0:
>         dic[key] = val + 2

> What should be preferred in this particular case . Kindly guide

If you rename the vars in the first to match the second:

dic.update((key, val+2) for key, val in dic.items() if val%2)

Then there is very little to separate them. The explicit
loop is maybe slightly easier to read for a beginner
but probably slower to execute.

To make the update even more readable I'd probably opt
for a dict comprehension update argument:

dic.update({key:val+2 for key, val in dic.items() if val%2})

-- 
Alan G
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