In Ruby, what is the cleanest way of obtaining the index of the largest value in an array?

Question

If a is the array, I want a.index(a.max), but something more Ruby-like. It should be obvious, but I\'m having trouble finding the answer at so and

Answer 1

Here is a way to get all the index values of the max values if more than one.

Given:

> a
=> [1, 2, 3, 4, 5, 6, 7, 9, 9, 2, 3]

You can find the index of all the max values (or any given value) by:

> a.each_with_index.select {|e, i| e==a.max}.map &:last
=> [7, 8]