test2.rb

#!/usr/bin/env ruby

class ArrayWithHashes

    def initialize(hashes)
       @hashes = hashes 
    end

    def find_by(selector)    
        @hashes.select do |h|
            selector.each do |k,v|
                break false unless h[k] == v
            end
        end
    end

end

hashes = [
  { id: 1, name: 'Pat', gender: 'f' },
  { id: 2, name: 'Pat', gender: 'm' },
  { id: 3, name: 'Steve', gender: 'm' },
  { id: 4, name: 'Sue', gender: 'f' },
]

i = ArrayWithHashes.new(hashes)

puts i.find_by({name: 'Pat'})
puts '----'
puts i.find_by({name: 'Pat', gender: 'm'})
puts '----'
puts i.find_by({})
puts '----'
puts i.find_by({id: 5})