Michael Edgar wrote in post #1012048:
> On Jul 21, 2011, at 2:27 AM, CC Chen wrote:
>
>> When I set an array k = [3,5,6,0,1,4,5,6,9,1]
>>
>> And I used the k.max can know the max value is 9
>>
>> How do I get the number "8" (as k[8] = 9)??
>
> k.index(k.max) will work. It's not completely optimal, but it's concise
> and asymptotically optimal.

:-)

Here's another approach which is a tad more involved and iterates the 
array only once:

irb(main):001:0> k = [3,5,6,0,1,4,5,6,9,1]
=> [3, 5, 6, 0, 1, 4, 5, 6, 9, 1]
irb(main):002:0> k.each_with_index.max_by {|e,i| e}.last
=> 8

Kind regards

robert

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