Hi Aaron, I think this approach may be more complicated than it's worth. I think I am going to try another approach, in which I will loop through a list of files, extract the 9th column of times, sum the ninth column, provide a counter to count the number of lines in the column that match the conditions I need, then find the mean by taking the total(sum) and dividing by that counter. The logic is provided below: 
 
    $total = 0;
    $count = 0;
 for ($j = 2; $j < @tableb; $j++) {
        chomp ($tableb[$j]);
        ($netsta,$delay_time) = (split /\s+/,$tableb[$j])[1,9];
        ($net,$sta) = (split /\./, $netsta)[0,1];
        if ($net eq "ZJ") {
            $count = $count + 1;
            $total = $total + $delay_time;
            $mean = $total/$count;
            print $mean, "\n";
        }

[download]
The for loop is looping through a file called $tableb, and if $net in the first column equals "ZJ", add to the counter, and then add the delay_time. Then I want to get the mean, and I output the mean. When printing out the mean, I get: 
 
-0.9188
-1.0063
-0.585466666666667
-0.705775
-0.80838
-0.80595
-0.722071428571429
-0.6714
-0.773888888888889
-0.84067
-0.9097
-0.958375

-0.7386
-0.7877
-0.784433333333333
-0.69155
-0.78836
-0.779766666666667
-0.820314285714286
-0.8476
-0.802544444444444
-0.88008
-0.9104
-0.916916666666666
-0.962815384615385
-1.0093

[download]
where the LAST value before each line break (-0.958375 and -1.0093) are the means that I need -- they are the total means. Now the question I have is, how do I extract that last value, set it to a variable, and then later on, subtract it from the $delay_time when I need to print it out (which isn't provided here)? TLDR: When printing out the means, the means iteratively add up, and then I need to extract the final mean once the for loop is finished looping through each column. That final mean (the total mean) will then be sent to a variable to be used for subtraction purposes later. Does that make sense? I apologize if it's not clear. One option I found was using the -1 option to extract the last line of each output. Would that work?

In reply to Re^2: Performing Mathematical Operation on Specific Column of text File by Bama_Perl
in thread Performing Mathematical Operation on Specific Column of text File by Bama_Perl

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