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来获取最大值（在本例中为0）的索引？

红宝石1.9.3

Answer 1

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

Answer 2

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