From: Bil Kleb <Bil.Kleb@...>
Date: 2009-07-02T21:20:19+09:00
Subject: delete_if_with_index or delete_at(array) in 1.8.6?

Hi,

Given an array of integers, I need to delete all those
entries that are lower than the current array index.

I first thought of the non-existent,

  array.delete_if_with_index{ |e,i| e < i }

then,

  remove_indices = []
  array.each_with_index{ |e,i| remove_indices << i if e < i }
  array.delete_at( remove_indices )

or the same, but with a fictious inject_with_index,

  remove_indices = inject_with_index([]){|acc,e,i| acc << i if e < i }
  array.delete_at( remove_indices )

and finally the 1.9 possibility,

  array.map_with_index!{ |e,i| e < i ? nil : e }.compact!

before compromising with

  array = (0...array.size).zip(array).map{ |i,e| e < i ? nil : e }.compact

Anything more elegant available?

Or perhaps an alternative way to attack the problem?

Thanks,
--
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