Remove duplicates from loop

Question

i have following code.

for i in 0..sold.length-1
    duplicate = sold[i]
    print duplicate.check_duplicates
    print \"     \"
    print sold[i].lotnumber + \         


        

Answer 1

The hash resulting from the group_by method can be used as a counting device; this does not use the check_duplicates method.

grouped = sold.group_by{|item| [item.lotnumber, item.serialnumber]}
grouped.each{|key, value| puts "#{value.size}   #{key.first}\t#{key.last}"}