How is max supposed to work, especially key.

[Steven D'Aprano]

Jussi Piitulainen wrote:


> Would you also want sorted called something else when used with a key?
> Because it doesn't produce a sorted list of the keys either:
> 
>   >>> data = ("short", "long", "average")
>   >>> sorted(data, key=len)
>   ['long', 'short', 'average']
>   >>> max(data, key=len)
>   'average'

I agree with the point you are making, but I disagree with the wording you
use. The result of calling sort() with key=len *is* sorted. It is sorted by
length of the word.

Same for calling max() with a key. The result is still the maximum value.
The difference is how you decide which of two elements is greater:

max(list_of_foods, key=calories)
max(list_of_foods, key=weight)
max(list_of_foods, key=cost)


That is three different ways to decide which is the maximal food in the
list: by number of calories, by weight, or by cost.




-- 
Steven