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

use strict;
use warnings;
use DDD::test2;
my $incr = 0;
my @array="";

undef $/;
open DATA, "san.txt" or die $!;

my @blocks = map { [ split /\n/ ] }
    ( split /(?=ITEM NO:)/, ( map { s/\#.*\n//; $_ } <DATA> )[0] );

while(1)
{
    
 @array = @{ $blocks[$incr] }; 
  if (@array eq "")
 {
print "There is no item remaining in the file";
last;
 }
test2::REQUEST(@array); 
$incr++;
}

#test2.pm contains

package test2;
sub REQUEST (@)
{
my @array=@_;
print "@array\n";
}
1;

#Suppose san.txt file contains


#This is the ITEM file
#This is a perl config file
# I am ok
ITEM NO:1
[aaa]
111
ffff
[bbb]
222
[ccc]
333
#This not taken
ITEM NO:2
[ddd]
444
[eee]
555
0000
[fff]
666
#This is not taken
ITEM NO:3
[ddd1]
4441
[eee1]
5551
[fff1]
6661
# I am sanjay
ITEM NO:4
...
...
...

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When i run the above program, the output comes as
#This is a perl config file # I am ok
ITEM NO:1 [aaa] 111 ffff [bbb] 222 [ccc] 333 #This not taken
ITEM NO:2 [ddd] 444 [eee] 555 0000 [fff] 666 #This is not taken
ITEM NO:3 [ddd1] 4441 [eee1] 5551 [fff1] 6661 # I am sanjay
ITEM NO:4 ... ... ...
Can't use an undefined value as an ARRAY reference at test1.pl line 12
+, <DATA> chunk 1

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Can you suggest me some suitable code so that while reading
the config file my program does not take the lines which is started with #. Also how to avoid the error 
"Can't use an undefined value as an ARRAY reference at test1.pl line 1
+2, <DATA> chunk 1"

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and also how can i operate the if block.
 if (@array eq "")
 {
print "There is no item remaining in the file";
last;
 }

[download]
Please Suggest me.

20061023 Janitored by Corion: Added formatting, put data in code tags

2006-10-23 Retitled by planetscape, as per Monastery guidelines

( keep:0 edit:9 reap:0 )

Original title: 'Suggest me some suitable code?'

Replies are listed 'Best First'.
Re: Problems reading records from file
by bingos (Vicar) on Oct 23, 2006 at 07:53 UTC

    The simplest way to parse config files would be use one of the many existing config file modules on CPAN, like Config::IniFiles for instance.

    Evaluating an array in a scalar context produces the number of items in the array. So your block should look like this:

    unless ( @array ) {
    print "There is no item remaining in the file";
    last;
}

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[reply]
[d/l]
Re: Problems reading records from file
by reneeb (Chaplain) on Oct 23, 2006 at 07:55 UTC
    You don't need a while-loop. You should use a for-loop.
    And the test if any element is in the array should be unless(@array){...}.
    You have to use the modifier g to delete "all" things from '#' to the end of line...

    #!/usr/bin/perl

use strict;
use warnings;

{
  local $/;
  open DATA, '<',"san.txt" or die $!;

  my @blocks = map { [ split /\n/ ] }
       ( split /(?=ITEM NO:)/, ( map { s/#.*?\n//sg; $_ } <DATA> )[0] 
+);
  close DATA;

  for(@blocks){
    my @array = @$_; 
    unless(@array){
      print "There is no item remaining in the file";
      last;
    }
    print "@array\n"; 
  }
}

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[reply]
[d/l]
[select]
      Hi
      Thanks a lot for your suggestion? It works fine according to my requirment. But this block is not executed at the end .
      unless(@array){
      print "There is no item remaining in the file";
      last;
    }

      [download]
      It does not print "There is no item remaining in the file" at the end.
[reply]
[d/l]
Re: Problems reading records from file
by jwkrahn (Abbot) on Oct 23, 2006 at 09:19 UTC
    Can you suggest me some suitable code
    Sure: 
    open FILE, '<', 'san.txt' or die "Cannot open 'san.txt' $!";

my $incr = -1;
my @array;
while ( <FILE> ) {
    chomp;
    next if /^\s*(?:#|$)/;
    $incr++ if /^ITEM NO:/;
    push @{ $array[ $incr ] }, $_;
    }

test2::REQUEST( @array );

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[d/l]

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