How to know how many times the same Object appears in Array? I want to check how many times I found the object, like:
array = ['A','A','A','B','B','C','C','C','D']
So, A appeared three times, B twice, C three too, and only one for D.
I know that if I use "find_all", like:
array.find_all{ |e| array.count(e) > 1 }
I will get with answer
["A", "A", "A", "B", "B", "C", "C", "C"]
but, how I can count this? I want something like:
A = 3, B = 2, C = 3, D = 1.
You can use inject on the array to iterate over the array and pass a hash into each iteration to store data. So to retrieve the count of the array you gave you would do this:
array = ["A", "A", "A", "B", "B", "C", "C", "C"]
array.inject(Hash.new(0)) do |hash, array_item|
hash[array_item] += 1
hash # this will be passed into the next iteration as the hash parameter
end
=> {"A"=>3, "B"=>2, "C"=>3}
Passing in Hash.new(0) rather than {} will mean that the default value for each key when you first encounter it will be 0.
