h_to_a_mapping.rb

class MyLittleProgram
    def execute
        h = { h1: 'value1', h2: 'value2', h3: 'value3', h4: 'value4' }
        a = [ '1', '2', '3', '4' ]
 
        h.each_with_index do |(k, v), i|
            break if a.size > h.keys.size

            a.each_with_index { |val, index|
                if i == index
                    h[k] = v.to_s + '_' + val.to_s
                end
            }
        end
    end
end

e = MyLittleProgram.new
p e.execute
# Output => h = { :h1 => "value1_1", :h2 => "value2_2", :h3 => "value3_3", :h4 => "value4_4" }