options choices list - generate all the possible combinations of a given number of choices and options to choose from

options_choices_list.rb

def binarylist(choices)

    list = Array.new(2**choices)
    (2**choices).times do |x|
        list[x]=[]
        choices.times do |y|
            if (x & 2**y)!=0
                list[x] << 1
            else
                list[x] << 0
            end
        end
    end
    
    return list
end


def optionschoiceslist(options,choices)
    
    list = binarylist(choices)
    current = 1
    3.upto(options) do
        newlist = [ ]
        list.length.times do |i|
            row = list[i]
            if row.include?(current)
                index = [ ]
                row.length.times do |j|
                    if row[j]==current
                        index << j
                    end
                end

                templist = binarylist(index.length)
                templist = templist.collect{|e1| e1.collect {|e2| e2 + current }}

                templist.length.times do |j|
                    temprow = row.dup
                    index.length.times do |k|
                        temprow[index[k]] = templist[j][k]
                    end
                    newlist << temprow
                end 
            else
                newlist << row
            end
        end
        current = current + 1
        list = newlist
    end
    
    return list
end

optionschoiceslist(4,3)