example_of_yield_recreating_map_and_select.rb

class Array 
    def my_map 
        new_arr = []
        self.each do |elem|
            new_arr << yield(elem)
        end 
        return new_arr
    end
    
    def my_select 
        filtered_arr = []
        self.each do |item|
            if yield(item)
                filtered_arr << item 
            end 
        end
        return filtered_arr 
    end
end 

arr = [1,17,4,9,12,11,6,10]

map_arr = arr.my_map do |item|
    item * 2
end 

select_arr = arr.my_select do |item|
    item % 2 == 0
end 

p map_arr
p select_arr