http://qs321.pair.com?node_id=1083675


in reply to parsing a multi-line pattern and replacing

Why are you using Tie::File? Doing line-based matching will be tricky. Unless your files are huge (many megabytes), slurping the entire file will be both faster and easier, and File::Slurp save you from worrying about any temp file mechanics:

use File::Slurp 'edit_file';
 
edit_file { s!<default>.+?</default>!<default>enabled</default>!sg } '
+inputfile';

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With the same inputfile you list, I get the expected output:

this is line 1
this is line 2
<default>enabled</default>
this is line 3
<default>enabled</default>
this is last line

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Have a look at File::Slurp for more information on this often overlooked but very handy function.

use strict; use warnings; omitted for brevity.

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Re^2: parsing a multi-line pattern and replacing
by ghosh123 (Monk) on Apr 25, 2014 at 04:55 UTC

    Many thanks for your suggestion.
    You all are correct, for ease of explanation I did not mention that the inputfile is a XML file.
    Basically I have a hash which contains the tags of xml and their default values .
    Now only those tags will be replaced which has a key in the hash. So the xml inputfile actually looks like :

    **********************************
    <user>
    <default>dean</default>
    </user>
    <id>
    <default>38339</default>
    </id>
    <workarea>
    <default>/home/dean</deault>
    </workare>
    ************************************

    And lets assume the hash has 2 keys for id and workarea :

    %hash = (id => 94848, workarea=> '/home/unix' )
    So in this case while parsing the xml , I will only replace <default> values for <id> and <workarea>

[reply]

      Hi,
      I could do it myself. Here goes the code 

      tie @array , 'Tie::File' ,  "$file" ;  

    foreach my $key (keys %varHash)
    {
        my $keyflag = 0 ;
        my $changedVal = $varHash{$key}{newVal};
        my $startdef = '<default>';
        my $enddef = '</default>';
        my $storedindex;
        
        print "key $key | changedVal $changedVal \n";
        for(my $i = 0 ; $i <= $#array ; $i++)
        {
            if($array[$i] =~ /$key/)
            {
                print "here $key \n";
                $keyflag = 1 ;
                next;
            }
            elsif ($array[$i] =~ /\<default\>.*?\<\/default\>/gs)

            {
                #    print "array[i] $array[$i] \n";
                if($keyflag)
                {
                    $array[$i] = "$startdef"."$changedVal"."$enddef";
                    $keyflag = 0;
                    last;
                }
            }
            elsif($array[$i] =~ /^\s*\<default>.*[^\>]$/)
            {
                $storedindex = $i ;
            }
            elsif($storedindex > 0 )
            {
                if ($array[$i] =~ /\<\/default\>/)
                {
                    my $range = $i - $storedindex;
                    splice(@array, $storedindex,$range);
                    $array[$storedindex] = "$startdef"."$changedVal"."
+$enddef";
                    last;
                }
            }                
            
        }            
    }

    untie(@array);

}

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