Given an array, I need to produce a two-dimensional resulting array

where each pair consists of a unique element from the original array

and the number of times that element appears.

I found two ways to do this. Is one of them better? Is there a better

way?

arr = %w{a b b c c d e e e}

p arr

p arr.uniq.map {|e| [e, (arr.select {|ee| ee == e}).size ]}

counter = {}

arr.each {|e| counter[e] += 1 rescue counter[e] = 1 }

p counter.to_a

outputs:

[“a”, “b”, “b”, “c”, “c”, “d”, “e”, “e”, “e”]

[[“a”, 1], [“b”, 2], [“c”, 2], [“d”, 1], [“e”, 3]]

[[“a”, 1], [“b”, 2], [“c”, 2], [“d”, 1], [“e”, 3]]