Paul And Joann Van Dalen wrote:
> Hi all,
>
> Given an input file that has the following records:
>
> 123 ABC XX112 YYYY Zzzzzzzzzz
> 123 DEF XX113 WWWW Zzzzzzzzz
> 123 EEF XX112 YYYY Zzzzzzzzzz
> 444 ccc vvbfd QQQQ ccccccccc
> 444 CCd vvbfd QQQQ ccccccccc
> 444 ddd ssddd QQQQ xxxxxxxx
>
> I need to focus on the first column (the input file is already sorted on
> that field) and, grouped by the first column, pull out
> the first record of that group.
> e.g., I would need to have the following from the above as output:
>
> 123 ABC XX112 YYYY Zzzzzzzzzz
> 444 ccc vvbfd QQQQ ccccccccc
>
> I believe I'd need something like a hash, where for every record within
> a group defined by the common value of the first column, I take the
> numerically first occurance of that group, but I don't know how to do
> that in Perl. Would it take a loop for each group within the loop for
> the entire file??
>
> Thanks very much,
> Paul
with a hash, try something like the following:
#!/usr/bin/perl -w
use strict;
my %hash;
open(DATA,'data.txt') || die $!;
while(<DATA>){
my ($number) = /^(\d+)/;
next if(exists $hash{$number});
$hash{$number} = $_;
}
close(DATA);
foreach my $key (sort {$a <=> $b} keys %hash){
print $hash{$key};
}
__END__
david
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
