@sortedarray=
 map{$_->[0]}  # return an array that only contains the original values (now sorted)
    # sort on $computedsortval
    # you use only use one of these sort lines
    sort{$a->[1] <=> $b->[1]} # this one for numerical sorting
    sort{$a->[1] cmp $b->[1]} # this one for textual sorting
    
    #this map block computes the value you're going to sort on 
    #and places it in $computedsortval

    map{
       #calculate $computedsortval
       [$_,$computedsortval];
    } @origarray;