How to count duplicates in Ruby Arrays

Question

How do you count duplicates in a ruby array?

For example, if my array had three a\'s, how could I count that

Answer 1

Another way to do it is to use each_with_object:

a = [ 1, 2, 3, 3, 4, 3]

hash = a.each_with_object({}) {|v, h|
  h[v] ||= 0
  h[v] += 1
}

# hash = { 3=>3, 2=>1, 1=>1, 4=>1 } 

This way, calling a non-existing key such as hash[5] will return nil instead of 0 with Kim's solution.