On 29 Aug 2020, at 13:42, Filipp Bakanov <filipp@bakanov.su> wrote:

I'd like to propose adding argmax and argmin functions to the python list. These functions return the index of a maximum / minimum element of the list. Eg:

a = [1, 4, 2, 3]

print(a.argmax())  # 1

print(a.argmin())  # 0

It's a very popular request (based on stackoverflow https://stackoverflow.com/questions/16945518/finding-the-index-of-the-value-which-is-the-min-or-max-in-python ), and currently there is no elegant way to find it.

What do you think?

Just do this:

>>> a=[1,4,2,3]

>>> min(a)

1

>>> a.index(min(a))

0

>>> a.index(max(a))

1

Barry

This has the drawback of passing twice over the list. The following doesn't, but the complexity somewhat makes Filipp's point:

>>> min((e, i) for i, e in enumerate(a))[1]
0

I think one would want argmin() and argmax() to work with general iterables, so I wonder if the stdlib would not be a better home than list itself. I half expected it to be an itertools recipe. The advantage of a recipe is that variations such as needing the last occurrence of the minimum are easily accommodated.

Jeff Allen