use strict;
my $str = '168-B-A-3, LIG Flats, yur Vihar Phase-3, Vasundhra nclave, East Delhi, Vasundhra nclave, Delhi, 110096';
my $regex = qr/(?P<Flat>([A-Za-z0-9\/\-]*\w\s*)*)(\,|\s|\|)*(?P<Building>([A-Za-z0-9\s\/\-]*\w\s*)(\,|\s)*)(?P<OtherPart>([A-Za-z\s\/\-\,]*\w\s*)(\,|\s)*)(?P<PinCode>([0-9]{6}))/mp;
my $subst = '\\1\\2 \\3';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html