Shlomi Fish wrote:
On Saturday 16 Apr 2011 09:06:02 Gurunath Katagi wrote:
hi .. i am new to perl ..
i have a input file something pasted as below ..
16 50
16 30
16 23
17 88
17 99
18 89
18 1
..
--
and i want the output something like this :
16 50 30 23
17 88 99
18 99 1
i.e for each values in the first column, i want the elements in the second
column to be a one row ..
can be anybody give me psuedocode , to how to go about this ..
thank you
This should work (tested):
Regards,
Shlomi Fish
----------------------------- SNIP ------------------------
#!/usr/bin/perl
use strict;
use warnings;
my $filename = shift(@ARGV);
open my $in_fh, '<', $filename
or die "Cannot open '$filename' for reading";
You should include the $! or $^E variable in the error message so you
know why it failed.
my $last_key = undef;
ICK!
my @values;
sub print_line
{
You are using a subroutine for this??? Really?
Why are you using global variables instead of lexically scoped
variables? You should know better.
print $last_key, ' ', join(' ', @values), "\n";
Or:
print join( ' ', $last_key, @values ), "\n";
Or even:
print "$last_key @values\n";
Is there really a good reason to make it more complicated than it needs
to be?
return;
}
while (my $line =<$in_fh>)
{
chomp($line);
my ($new_key, $new_value) = split(/\s+/, $line);
What if there is leading whitespace?
You do realize that split(/\s+/) removes ALL (trailing) whitespace so
using chomp() is redundant.
if ( ( !defined($last_key) ) or ($last_key eq $new_key))
{
push @values, $new_value;
}
else
{
print_line();
@values = ($new_value);
}
$last_key = $new_key;
}
print_line();
close ($in_fh);
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
direction. -- Albert Einstein
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