Hello akamboj84, and welcome to the Monastery!

You first create a dictionary mapping each search regex to its corresponding replacement text. Then, before searching, you change the search regex in two ways: (1) by concatenating all the search strings with |; (2) by applying the qr operator. So when you get to the substitution, if a match is found the dictionary lookup $dic{$matchkey} is guaranteed to fail, since the new value of $matchkey does not match any of the keys in the %dic hash!

But even when this problem has been fixed,¹ you will still be replacing the whole of the first user entry, including everything through to the final "engineer", with the single text REPLACE1. I doubt this is what you want. For the monks to help you further, you will need to specify the output you expect/desire.

Update: ¹For example:

Hope that helps,

Hi Athanasius, Thanks for that stuff. But I already have a working code like this. But I wanted to avoid the below "for" loop and instead do multi regex replacement.

for my $matchkey (keys %dic)
{
   $line =~ s%$matchkey%$dic{$matchkey}%g;
}
[download]

Also for each regex I have seperate set of pre defined replacement String not like Replace1 or Replace2( that was just used as an example) and I want replace the complete matched string with predefined Replacement String.

Hello again, akamboj84,

But I wanted to avoid the below "for" loop and instead do multi regex replacement.

...as my regex file is a long one and also i need to process a lot of files, so its kind of time/cpu consuming. I want to get rid of "for" loop...
— Re^3: Multiline Regex replacement in Multiline file

There may be some clever way to do this using Perl’s extended regular expression patterns, but if so I haven’t found it. But deployment of the for loop can likely be made much more efficient. At present, the regexen are being applied to the whole input file; but if you can read in a paragraph at a time, this will save a lot of processing, as there will then be no need for the regex engine to re-search those parts of the input string that have already been matched and replaced:

Read more... (2 kB)

Hope that helps,

Athanasius <°(((>< contra mundum

Iustus alius egestas vitae, eros Piratica,

Howdy akamboj84,

$line =~ s%$matchkey%$dic{$&}%g;    # Use the matched string as a key 
+in $dic
$line =~ s%($matchkey)%$dic{$1}%g;  # Same as above without the perfor
+mance issues of $&
[download]

Hello Grimy,

This is a nice idea, but unfortunately, as long as the regex contains metacharacters, it can’t be made to work, because $1 will never contain those metacharacters:

#! perl
use strict;
use warnings;
use Data::Dump;

my $re  = 'aaa\s+bbb';
my %dic = ($re => 'new');
my $s   = 'aaa   bbb';

$s =~ s/($re)/$dic{$1}/;

print "\$1   = $1\n";
print "\$s   = $s\n";
print "\%dic = ";
dd     \%dic;
[download]

Output:

19:34 >perl 1011_SoPW.pl
Use of uninitialized value within %dic in substitution iterator at 101
+1_SoPW.pl line 10.
$1   = aaa   bbb
$s   =
%dic = { "aaa\\s+bbb" => "new" }

19:34 >
[download]

Sorry, :-(

Athanasius <°(((>< contra mundum

Iustus alius egestas vitae, eros Piratica,

Hello Athanasius, Is there any workaround for this ? as my regex file is a long one and also i need to process a lot of files, so its kind of time/cpu consuming. I want to get rid of "for" loop as mentioned in reply to your previous post