Comments on: Computing argmax fast in Python

By: argmax in Python | Tastalian's Blog

argmax in Python | Tastalian's Blog — Tue, 24 Apr 2012 22:55:01 +0000

[...] called the “argmax” of (f) on (C). One can find solutions for this on-line, e.g. in this blog post, but I realized recently that Python’s max() function can actually handle the job. Here is [...]

By: Anonymous

Anonymous — Wed, 27 Apr 2011 15:59:01 +0000

How about

max(xrange(len(array)), key=array.__getitem__)

By: Mapio

Mapio — Sat, 29 Jan 2011 16:41:33 +0000

In case of duplicate values you solution returns the last position, while the array.index(max(array)) solution returns the first which, beside the simplicity of the solution, seems to be the more natural answer.

By: Sam

Sam — Thu, 18 Dec 2008 13:48:34 +0000

import numpy

array = numpy.array ( [1,2,4,3,5,1 ] )

numpy.argmax( array )

# should return 4

By: Fast argmax in Python

Fast argmax in Python — Wed, 17 Dec 2008 13:48:17 +0000

[...] my post Computing argmax fast in Python, I reported that Python has no builtin function to compute argmax, the position of a maximal value. [...]

By: kralin

kralin — Wed, 17 Dec 2008 11:27:24 +0000

array.index(max(array))

is it too simple?

By: Protector one

Protector one — Wed, 07 May 2008 20:31:05 +0000

I’m sorry SwiftCoder, but I believe that is a max. It is equivalent to:

m = max(array)

My (arg)max:

lambda array: max([array[i],i] for i in range(len(array)))[1]

Cheers!

By: SwiftCoder

SwiftCoder — Tue, 29 Jan 2008 14:20:38 +0000

You should also try a functional idiom – typically better and faster:

array = [1.0, 2.0, 3.0, 1.0]

m = reduce(max, array)

By: Anonymous

Anonymous — Sun, 13 Feb 2005 14:16:10 +0000

You can try this:

def positionMax(sequence, excludedIndexesSet=None):
if not badindexes:
return max( izip(sequence, xrange(len(sequence)) ) )[1]
else:
badindexes = set(badindexes)
return max( (e,i) for i,e in enumerate(sequence) if i not in badindexes )[1]