Help in reading log file

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

Hi Monks,

I have to read lines from a log file which begins with // with some white spaces before and put them in a array so below is the code what i could write and this works. But i want to know if i can remove the spaces before pushing into array instead of using s/^\s+//g; in foreach loop while printing and also i want to ignore the lines with -// which is getting included.

open (FH,"$file") || die ("could not openfile");
my @arr;
while (<FH>) {
chomp;
push @arr , $_  unless $_ !~ /\s+\/\// ;
}
foreach (@arr){
s/^\s+//g;
s/^-\/\/.+//g;
print $_."\n";
}

Thanks in advance.
[download]

Comment on Help in reading log file Download Code

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Re: Help in reading log file by hipowls (Curate) on Mar 14, 2008 at 08:51 UTC
There are a few things I'd do differently, first the open I'd write as `open my $FH, '<', $file or die "Can't open $file: $!\n";` [download] The lexical file handle `$FH` is limited is scope to just the block of code it appears in so won't clobber file handles opened else where. Probably not a concern for a short script but it still a good habit. The three argument form of open where the open mode is specified separately is safer especially when `$file` comes from an untrusted source. I use low precedence `or` so I can get rid of the brackets I put `$!` in the error message so I know why the open failed. The loop I'd rewite as this `use Data::Dumper; my @arr; while (<DATA>) { chomp; push @arr, $1 if m{^ +\s+(//.*)}; } print Dumper \@arr; __DATA__ // humpty dumpty // sat on a wall -// eating her curds and whey // humpty dumpty // had a great fall` [download] which produces `$VAR1 = [ '// humpty dumpty', '// sat on a wall', '// humpty dumpty', '// had a great fall' ];` [download] Just a couple of points I use `m{ }` to avoid the leaning toothpicks. I use capturing parentheses to grab the bit of string I want, if there is a match it is in $1 and it is pushed onto the array	[reply] [d/l] [select]
Re: Help in reading log file by Punitha (Priest) on Mar 14, 2008 at 07:05 UTC
Hi On modifying your code, you can try like this, `open (FH,"$file") \|\| die ("could not openfile"); my @arr; while (<FH>) { chomp; push @arr , $1 if $_ =~ /\s+(\/\/.+)/; }` [download] Punitha	[reply] [d/l]
Re: Help in reading log file by jwkrahn (Abbot) on Mar 14, 2008 at 07:08 UTC
It appears that lines with `-//` are included because you don't anchor the pattern `/\s+\/\//` to the beginning of the line. So it looks like you probably want something like: `open FH, '<', $file or die "could not open '$file' $!"; my @arr; while ( <FH> ) { chomp; push @arr, $_ if s!^\s+(?=//)!! ; } foreach ( @arr ){ print "$_\n"; }` [download]	[reply] [d/l] [select]
Re: Help in reading log file by poolpi (Hermit) on Mar 14, 2008 at 07:11 UTC
`#!/usr/bin/perl use strict; use warnings; use Data::Dumper; my @arr; while (<DATA>){ chomp; push @arr, $_ if s/ \s+ ( [\/]{2} .+ ) /$1/xms; } print Dumper \@arr; __DATA__ //opiopiopi -//popoiop uytyu --- //llmùlùm //fghfghf -//sdsdfsdfs` [download] `Output : $VAR1 = [ '//opiopiopi', '//llmùlùm', '//fghfghf' ];` [download] hth, PooLpi 'Ebry haffa hoe hab im tik a bush'. Jamaican proverb	[reply] [d/l] [select]