i have hash departments
{"Mechnical" => {"boys" => "25", "girls"=>"5"}, "Civil"=> {"boys"=>"18", "girls"=>"12"}}
i want output like this,
{"Mechanical" => "30", "Civil => "30"}
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2 Answers
Do as below
# If you are in Ruby 2.1 or greater
your_hash.map { |k,v| [k, v.reduce(0) { |sum, (_, v)| sum + v.to_i }] }.to_h
# => {"Mechnical"=>30, "Civil"=>30}
# below Ruby 2.1
Hash[your_hash.map { |k,v| [k, v.reduce(0) { |sum, (_, v)| sum + v.to_i }] }]
# => {"Mechnical"=>30, "Civil"=>30}
# for all versions
your_hash.each_with_object({}) do |(k,v), h|
h[k] = v.reduce(0) { |sum, (_, v)| sum + v.to_i }
end
# => {"Mechnical"=>30, "Civil"=>30}
Comments
hsh = { "Mechnical" => {"boys" => "25", "girls"=>"5"}, "Civil"=> {"boys"=>"18", "girls"=>"12"} }
hsh.map { |d, s| [d, s.sum {|_, c| c.to_i} ] }.to_h
# => {"Mechnical"=>30, "Civil"=>30}
If count is a number rather than a String, you can do
hsh.map { |d, s| [d, s.sum(&:last) ] }.to_h
# => {"Mechnical"=>30, "Civil"=>30}
Since you are using Rails, sum will work, other wise use inject(:+)
Thanks Arup for pointing out the redundancy of 2 intermediate arrays.
EDIT
Ruby has Enumerable#sum since 2.4.0
1 Comment
Arup Rakshit
Why did you suggest 2 extra intermediate arrays ? (
v.values.map(&:to_i))