the $i is in the code below:

 # save the values from the 2-dimensional into a 1-dimensional array
 for $i ( 0 .. $#vals ) {
     $tot_mem[$count] = $vals[$i][1];
     $count++;
 }
 my $tot_mem_sum = 0;
 # calculate the total of all values
 for $i ( 0 .. ($count-1) ) {
     $tot_mem_sum = $tot_mem_sum + $tot_mem[$i];
 }
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