need help on unopened file handle

tuakilan has asked for the wisdom of the Perl Monks concerning the following question:

Hi guys,

This is continued from http://www.perlmonks.org/?node_id=668491

i patched the following code provided by svenXY into the server:

#!/usr/local/bin/perl -w
use strict;
use warnings;
use DateTime::Format::Strptime;
my $Strp = new DateTime::Format::Strptime(pattern     => '%Y-%b-%d %T'
+,);
my $infile = 'logfile.2008-02-25.log';
my $outfile = 'report-2008-02-25.txt';
my($fh_out, $fh);
my %lookup;
my $channel = 'two';
my $time_delta = 3600;  # seconds = 1 hour
open($fh_out, '>', $outfile) or die "Could not open outfile: $!";
# open($fh, '<', $infile) or die "Could not open logfile: $!";
while (<DATA>) {
    next unless /$channel/;
    $_ =~ m/^(.*) UTC.*refs = (\d+)$/;
    my $dt = $Strp->parse_datetime($1);
    my $timestamp = $dt->epoch();
    my $refs = $2;
    if ( defined($lookup{$refs}) && $lookup{$refs} + $time_delta <= $t
+imestamp ) {
        print $fh_out "REFS $refs: occurrences at " . $lookup{$refs} .
+ "and $timestamp \n";
        print "REFS $refs: occurrences at " . $lookup{$refs} . " and $
+timestamp \n";
    }
    $lookup{$refs} = $timestamp;
}
close $fh_out;
#close $fh;
[download]

when i try to run the program, it vomited out the following error:

Name "main::DATA" used only once: possible typo at a3.pl line 24.
readline() on unopened filehandle DATA at a3.pl line 24.
[download]

The logfile.txt looks like this

2007-Nov-07 00:00:00 UTC (GMT +0000) - Poll: channel = ONE, ref =
2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = THREE, ref =
2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:04 UTC (GMT +0000) - Poll: channel = TWO, ref =
[download]

any clue on how to fix this ?

Comment on need help on unopened file handle Select or Download Code

Replies are listed 'Best First'.
Re: need help on unopened file handle by McDarren (Abbot) on Feb 28, 2008 at 06:48 UTC
Change your "while" line to read: `while (<$fh>) {` [download] And uncomment the line that opens that filehandle. The DATA filehandle usually refers to some embedded data at the end of the code, which starts after the `__DATA__` line. It's quite often used in examples. I suspect that you copied some code verbatim, without realising you needed to change that ;) Cheers, Darren :)	[reply] [d/l] [select]
Re: need help on unopened file handle by ikegami (Patriarch) on Feb 28, 2008 at 07:11 UTC
By the way, `my $channel = 'two'; next unless /$channel/;` should be `my $channel = 'TWO'; next unless /$channel/;` or `my $channel = 'two'; next unless /$channel/i;` Better yet, since `$channel` contains text and not a regex, you should use `my $channel = 'TWO'; next unless /\Q$channel\E/;` or `my $channel = 'two'; next unless /\Q$channel\E/i;` Also, I wouldn't rely on `$1` and `$2` to have remained unchanged after calling two methods.	[reply] [d/l] [select]
Re: need help on unopened file handle by munni (Novice) on Feb 28, 2008 at 07:21 UTC
Why have you commented out this line? `# open($fh, '<', $infile) or die "Could not open logfile: $!";` Uncomment it and use `while(<$fh>)` as mentioned above	[reply] [d/l] [select]
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