Hi I have a file with data like this.

-1 2 ereu
1 2 rerer
2 2 rere
3 2 eee
3 2 wwwe
9 2 qqewew
9 2 vvvgf
-1 2 wwwew
4 3 wwew
-9 3 wwss
6 3 jjuu
7 3 kkii
7 3 ggtyu
8 3 ffder
1 4 rrtrr
1 4 rree

[download]

If the values in 2nd column are same, calculate the minimum value in the first column and print corresponding lines. My desired output is;

-1 2 ereu
-1 2 wwwew
-9 3 wwss
1 4 rrtrr
1 4 rree

[download]

I wrote a code like this.

#! usr/bin/perl
use warnings;
use strict;
my @a = <> ;
my @b = ();
foreach (@a) {
 push (@b, split(/ /));
             }
my $i = 0;
my $j = 1;
my $min = $b[0];
my $x = 0;
while ($x++ < 150) {
    $j = $j+3;
    $i = $i+3;
 
        if ($b[$j] = $b[$j+3]) {

          if ($min > $b[$i]) {
                                   
                    $min = $b[$i]
                             }
                         
                               }
                   }

 print "$min\n";

[download]

But the code ignores the condition if ($b$j = $b$j+3) and prints just the minimum value of first column. My idea was to use a regex involving the minimum value to print the corresponding lines. Obviously I am a newbie to Perl. Can experts help me please? thanks in advance.

In reply to Selective Printing of Lines by polsum

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