Re^2: Substitution backreference woes

That seems to produce the same result, namely:

string is now Goodbye \1

#!/usr/bin/perl
use strict;
use diagnostics;
use warnings;

my $string = 'Hello sailor';
my $regex = 'Hello (.*)';
my $substitution = 'Goodbye \\1';

$string =~ s/$regex/$substitution/;
print "string is now $string \n";

# I wanted:     string is now Goodbye sailor
# I got:          string is now Goodbye \1
[download]

Comment on Re^2: Substitution backreference woes Download Code

Replies are listed 'Best First'.
Re^3: Substitution backreference woes by LanX (Saint) on Jan 24, 2015 at 13:17 UTC
yeah sorry I wasn't able to test from Android, the problem is that the substitution part of s/// is supposed to be a literal. Otherwise you have to apply the /e eval modifiers. `my $string = 'Hello sailor'; my $regex = 'Hello (.)'; # my $substitution = 'Goodbye \1'; $string =~ s/$regex/Goodbye $1/; print "string is now <$string> \n";` [download] `/usr/bin/perl -w /tmp/regex.pl string is now <Goodbye sailor>` [download] Please note that \1 is somehow deprecated in the substitution part and will cause warnings. Its only legitimate use is in the match part for backreference. Cheers Rolf PS: Je suis Charlie!*	[reply] [d/l] [select]
Re^3: Substitution backreference woes by LanX (Saint) on Jan 24, 2015 at 13:27 UTC
That's how you go if you want to hold the substitution part in a variable. `my $string = 'Hello sailor'; my $regex = 'Hello (.)'; my $substitution = '"Goodbye $1"'; $string =~ s/$regex/$substitution/ee; print "string is now <$string> \n";` [download] `/usr/bin/perl -w /tmp/regex.pl string is now <Goodbye sailor>` [download] Cheers Rolf PS: Je suis Charlie!*	[reply] [d/l] [select]
Re^4: Substitution backreference woes by Anonymous Monk on Jan 24, 2015 at 13:59 UTC
Yes, that seems to work perfectly. Thank you.	[reply]