Andrej Kastrin am Mittwoch, 18. Januar 2006 10.49:
> Dear Perl users,
>
> what's the best way to transform column table in row format. I know how
> to split each line according to delimiter and than put it separately
> into array, but I have more complicated problem (with multiple equal
> records in the first column)
>
> id001 text1
> id001 text2
> id001 text3
> id002 text23
> id002 text555
> id003 text666
>
> and want something like:
>
> id001 text1 text2 text3
> id002 text23 text 555
> id003 text666
Ok, in addition to my apologies, I present here the script I described in my
last post.
In constrast to the other presented solutions using a a hash slurping all data
from the intput file, the advantage of my solution is that it is
*capable to handle 300GB input files* even with 128MB RAM.
===
#!/usr/bin/perl
use strict;
use warnings;
# open input file here if source is not <DATA>
open (my $outf, '>', './andrey_kastrin.out.txt')
or die "Can't open file: $!";
my $old_name='';
while (<DATA>) {
chomp;
my ($name, $value)=$_=~/^([\w]+)\s+(.*)$/;
if ($old_name ne $name) {
print $outf "\n" if $old_name;
print $outf $_;
}
else {
print $outf ' ',$value;
}
$old_name=$name;
}
close $outf or die "Can't close file: $!";
# close input file here if source is not <DATA>
__DATA__
id001 text1
id001 text2
id001 text3
id002 text23
id002 text555
id003 text666
===
It outputs:
id001 text1 text2 text3
id002 text23 text555
id003 text666
I'm a nice guy, see?
joe
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