Hi Monks, Given the following input: 
 MCCC processed: unknown event at: Tue, 14 Oct 2014 12:02:26 CST 
station, mccc delay,    std,    cc coeff,  cc std,   pol   , t0_times 
+ , delay_times
 ZJ.GRAW    -0.7964    0.0051    0.9690    0.0139    0  GRAW.BHZ   301
+.1263    -1.8041
 ZJ.KNYN     -0.7065    0.0072    0.9760    0.0133    0  KNYN.BHZ   30
+1.3372    -1.9249
 ZJ.LEON      0.9675    0.0072    0.9548    0.0292    0  LEON.BHZ   30
+1.2611    -0.1749
 ZJ.RKST     -0.2061    0.0114    0.9404    0.0383    0  RKST.BHZ   30
+1.3500    -1.4374
 ZJ.SHRD      0.4382    0.0051    0.9542    0.0351    0  SHRD.BHZ   30
+1.7360    -1.1791
 ZJ.SPLN      0.3033    0.0051    0.9785    0.0126    0  SPLN.BHZ   30
+1.0760    -0.6541
Mean_arrival_time:   300.1187 
No weighting of equations. 
Window:   2.23   Inset:   1.17  Shift:   0.25 
Variance: 0.00645   Coefficient: 0.96215  Sample rate:   40.000 
Taper:   0.28 
Phase: P        
PDE    2013  7 15 14  6 58.00   -60.867   -25.143   31.0  0.0  7.3

[download]
What I want to do is take the ninth column (delay_times), and remove the mean from each of those values, and then output the same type of file (same formatting) to a new file. Here's what I have so far: The first two lines never change: 
 
#!/usr/bin/perl
use strict;
use warnings;

open my $file, '<', "file.txt" or die $!;
open my $out, '>', "newfile.txt" or die $!;
for (1..2) {
    my $constant = <$file>;
    print $out $constant;
}
while (<$file>) {
    my ($name, $time) = (split /\s+/, $file)[1,9];
    my ($net, $sta) = (split /\s+/, $name)[0,1];
    if ($net eq "ZJ") {
        
    }
    # Calculate the mean of the 9th column for every first column that
+ begins with ZJ,
    # and subtract the mean from each value (time) in the 9th column.
}


# Output the new file with the mean removed from each "time" in the 9t
+h column

[download]
Any help would be appreciated!

In reply to Performing Mathematical Operation on Specific Column of text File by Bama_Perl

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