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

This it the code: 
if ($line[0]=~ /^c/)
        {
                $line =~/(0x[A-Fa-f0-9]+).*(0x[A-Fa-f0-9]+).*((unit=([
+0-9]+)))/i;
                my @error = ($1, $2);
                my $value1= hex $error[0];
                my $value2= hex $error[1];
                my $unit= $5;

                $line =~/(port=([0-9]+))/i;
                my $port= $2;

                print "Value1: $value1,Value2:  $value2, Unit: $unit,P
+ort1:  $port,Stat: $line[6]\n";

        }



----data------
Ctl  Date                        Severity  Alarm Message
----------------------------------------------------------------------
+--------
c0   [Mon Apr 10 15:12:42 2006]  INFO      (0x04:0x000B): Rebuild star
+ted: unit=0
c0   [Mon Apr 10 15:12:09 2006]  INFO      (0x04:0x003B): Rebuild paus
+ed: unit=0
c0   [Mon Apr 10 15:08:28 2006]  INFO      (0x04:0x000B): Rebuild star
+ted: unit=0
c0   [Mon Apr 10 15:06:31 2006]  ERROR     (0x04:0x0002): Degraded uni
+t: unit=0, port=1
c0   [Mon Apr 10 15:06:31 2006]  WARNING   (0x04:0x0019): Drive was re
+moved from a bay: port=1

[download]
The prob:

The $2 value is wrong in the print out when there is no port... so I would need to delete it but $2 is read-only :-)

Any idea??

Thanks for the help

2006-04-11 Retitled by g0n, as per Monastery guidelines
Original title: 'matching pattens'

Replies are listed 'Best First'.
Re: matching patterns
by Corion (Patriarch) on Apr 11, 2006 at 07:02 UTC

    I said it in the CB already:

    Never use an unguarded assignment after a regex match. Always do 
    die "No data found" unless /...(...)/; 
my $value = $1;/

    [download]
    or do 
    my $value; if (/...(...)/) { $value = $1 };

    [download]

    In your case, this amount to:

    ...
    my $port = '<no port found>';
    if ($line =~/(port=([0-9]+))/i) {
        $port= $2;
    };

    [download]
[reply]
[d/l]
[select]
      Thanks for the help.. didn't get it in the CB... now it does the trick
[reply]
Re: matching patterns
by Zaxo (Archbishop) on Apr 11, 2006 at 07:18 UTC

    Your regex is complicated and likely to be buggy. The use of greedy .* may blow up in your face.

    What is @line, and what is its relation to $line?

    I'd get at the match variable problem like this: 

    if ($line[0] =~ /^c/) {
    # . . .
    my $unit = ($line =~ /\bunit=(\d*)/) ? $1 : '';
    my $port = ($line =~ /\bport=(\d*)/) ? $1 : '';
    # . . .
}

    [download]
    With that, the $unit and $port variables can only be assigned from $1 if the match succeeded and the value fresh. If the match fails the empty string is assigned, which will save warnings about undefined values when you print.

    After Compline,
    Zaxo

[reply]
[d/l]
      Thanks Zaxo but that would be ok if I only needed unit and port vlaue.. but I need others from the string as well.. but those are always there so it was no prob (one int and 2 hex values)... here is the script I got now ... and it works fine: 
      open ERASER,">output.txt";
close ERASER;

open ERRORLOG, "<error.txt" or die "Can't read file error: $!\n";
open OUTPUT,">>output.txt" or die "Can't read file $!\n";


while( my $line = <ERRORLOG> )
{
        chomp $line;
        @line=split " ",$line;

        if ($line[0]=~ /^c/)
        {
                $line =~/(c([0-9]+)).*(0x[A-Fa-f0-9]+).*(0x[A-Fa-f0-9]
++)/;
                my $conn = $2;
                my @error = ($3, $4);
                my $value1= hex $error[0];
                my $value2= hex $error[1];

                my $unit = '';
                if ($line =~/(unit=([0-9]+))/)
                {
                        $unit= $2;
                };

                my $port = '';
                if ($line =~/(port=([0-9]+))/)
                {
                        $port= $2;
                };

                print OUTPUT "Conn: $conn, Value1: $value1,Value2:  $v
+alue2, Unit: $unit,Port1:  $po
rt,Stat: $line[6]\n";

        }
}

close ERRORLOG;
close OUTPUT;

      [download]
[reply]
[d/l]
        Perhaps a minor point, but why are you capturing "port=" and "unit=" in your regexes 
        if ($line =~/(port=([0-9]+))/)

        [download]
        ? Couldn't it just as easily be 
        if ($line =~/port=([0-9]+)/){
                        $port= $1;
                };

        [download]


        -----------------
        s''limp';@p=split '!','n!h!p!';s,m,s,;$s=y;$c=slice @p1;so brutally;d;$n=reverse;$c=$s**$#p;print(''.$c^chop($n))while($c/=$#p)>=1;
[reply]
[d/l]
[select]

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