Given I have a HUGE array and a value from it I want to get index of the value in array Is there any other way rather then call Array index to get it The problem comes from the need of keeping really huge array and calling Array index enormous amount of times After a couple of tries I found that caching indexes inside elements by storing structs with value index fields instead of the value itself gives a huge step in performance 20x times win Still I wonder if there s a more convenient way of finding index of en element without caching or there s a good caching technique that will boost up the performance

Get index of array element faster than O(n)

Why not use index or rindex?

array = %w( a b c d e)
# get FIRST index of element searched
puts array.index('a')
# get LAST index of element searched
puts array.rindex('a')

index: http://www.ruby-doc.org/core-1.9.3/Array.html#method-i-index

rindex: http://www.ruby-doc.org/core-1.9.3/Array.html#method-i-rindex

~ Answered on 2012-07-24 08:05:14