in reply to Re^2: Shorten a list...
in thread Shorten a list...

There may be other ways than this. If the file is large (MB or GB), you might not want this method. It reads the whole file into an array, @data, before printing. 
#!/usr/bin/perl
use strict;
use warnings;

my (@buffer, @data);
while (<DATA>) {
    if (/^Group/) {
        push @data, [@buffer] if @buffer > 2;
        @buffer = $_;   
    }
    else {
        push @buffer, $_;   
    }
}

push @data, [@buffer] if @buffer > 2;

{
    local $" = '';
    print join("\n", map "@$_", @data);
}

[download]
Chris

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Re^4: Shorten a list...
by la (Novice) on Oct 17, 2011 at 21:51 UTC

    Thanks for the response. I have tried this script and still have the singlets being printed. Is there a way to get rid of the singlets (eg. only print groups 3 and 5 final output)?

[reply]
      My code ran fine on the sample you provided. Is this exactly how the file looks? 
      __DATA__
Group 1
name
Group 2
name
Group 3
name
name
Group 4
name
Group 5
name
name
name
Group 11
name
name
Group 15
name
name
name

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[reply]
[d/l]

        I guess it would have helped if I was more specific in exactly what my file looks like. Sorry about that. In reality, there are thousands of groups and my input file looks like this:

        
>Group 42
0    25ap, >name_06-T_1_0... at 92.00%
1    28ap, >name_06-T_1_0... *

>Group 43
0    28ap, >name_07-N_1_0... *

>Group 44
0    29ap, >name_07-N_1_0... *

>Group 45
0    25ap, >name_03-T_1_0... *
1    25ap, >name_06-T_1_0... at 100.00%
2    25ap, >name_07-N_1_0... at 100.00%
3    25ap, >name_11-N_1_0... at 100.00%
4    25ap, >name_14-T_1_0... at 100.00%

        [download]

        I would want an output that looks like this:

        >Group 42
0    25ap, >name_06-T_1_0... at 92.00%
1    28ap, >name_06-T_1_0... *

>Group 45
0    25ap, >name_03-T_1_0... *
1    25ap, >name_06-T_1_0... at 100.00%
2    25ap, >name_07-N_1_0... at 100.00%
3    25ap, >name_11-N_1_0... at 100.00%
4    25ap, >name_14-T_1_0... at 100.00%

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