如何在Ruby中使用max_by和with_index？

Question

a = %w(albatross dog horse)
a.max_by {|x| x.length }   #=> "albatross"

如何使用max_by.with_index获取最大值的索引（在本例中为0）？

Ruby 1.9.3

Answer 1

a.each_with_index.max_by { |x,i| x.length }.last

Answer 2

找到它：a.each_with_index.max_by {|x, idx| x.length }