Finding the index of an item using a block

Posted Friday, April 18, 2008

Update: Ruby 1.8.7 also has this.

Ruby 1.9 has it but if you’re not that bleeding edge, you can have it now:

class Arraydef index_with_block(*args)
  return index_without_block(*args) unless block_given?
  each_with_index do |entry, index|
    return index if yield(entry)
  end
  nil
end
alias_method :index_without_block, :index
alias_method :index, :index_with_block

def rindex_with_block(*args)
  return rindex_without_block(*args) unless block_given?
  index = sizereverse_each do |entry|
    index -= 1
    return index if yield(entry)
  end
  nil
end
alias_method :rindex_without_block, :rindex
alias_method :rindex, :rindex_with_blockend