in reply to Re: Perl solution for current batch file to extract specific column text
in thread Perl solution for current batch file to extract specific column text

This prints line 1 twice
#!perl
use strict;
while (my $line = <DATA>){
  if ($line =~ /line 1/){
    print $line;
    next for 1..5; # skip 5 lines
    print $line;
  }
}
__DATA__
line 1
line 2
line 3
line 4
line 5
line 6
line 7

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Perhaps you meant

#!perl
use strict;
while (my $line = <DATA>){
  if ($line =~ /line 1/){
    print $line;
    <DATA> for 1..5;
    $line = <DATA>;
    print $line;
  }
}

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poj

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Re^3: Perl solution for current batch file to extract specific column text
by Laurent_R (Canon) on Aug 04, 2015 at 12:04 UTC
    Yes, poj, you're right, there were two mistakes.

    This is the amended (and tested) version: 

    use strict;
use warnings;

my $input = "input.txt";
open my $IN, "<", $input or die "cannot open $input $!";
my $output = "output.txt";
open my $OUT, ">", $output or die "cannot open $output $!";
while (my $line = <$IN>) {
    chomp $line; # remove newline character from end of line
    if ($line =~ /INTERPOLATED HYDROGRAPH AT (\w+)$/){
        print $OUT $1;
        $line = <$IN> for 1..6; # skip 5 lines
        my $val2 = (split / /, $line)[1]; # get the second column
        print $OUT " $val2";
        $line = <$IN>for 1..2; # skip one line
        chomp $line;
        my $val3 = (split / /, $line)[-1]; # get the last column
        print $OUT " $val3\n"; 
    }
}

    [download]
    And this is the output: 
    $ cat output.txt
CAC40 1223. 1456.

    [download]
    I should add that this is not very robust code, it will probably break with any irregularity in the input data. But we would need to know more about the data (having at least three or four samples of line groups, instead of only one) to be able to do something more robust.
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