counting duplicates in ruby array and storing in hash

Question

I have a array coming from a mysql query like this

section, views
aa, 2
aa, 100
bb, 2
bb, 3
bb, 100

and I am using this code to sort it

b = Hash.new(0)
array.each do |row|
  ....
  ....
  b[section] += 1
end

which currently gives me a result hash for b[2]

aa,2
bb,3

Now I want the mysql query to filter the views for smaller and larger than 50 for example and would like the result to be

section,small,large
aa,1,1
bb,2,1

How do I implement this? Or would it be easier to do something like this:

aa_small,1
aa_large,1
bb_small,2
bb_large,1

ie keep them as separate hashes?

Answer 1

If I got it right you need something like:

views = 
    [['aa', 2],
     ['aa', 100],
     ['bb', 2],
     ['bb', 3],
     ['bb', 100]]

views
  .group_by(&:first)
  .map { |v, vs| [v, vs.partition { |_, x| x < 50 }
                       .map(&:length)] }
# => [["aa", [1, 1]], ["bb", [2, 1]]]

or if you want Hash:

Hash[views
       .group_by(&:first)
       .map { |v, vs| [v, vs.partition { |_, x| x < 50 }
                            .map(&:length)] }]
# => {"aa"=>[1, 1], "bb"=>[2, 1]}