http://www.perlmonks.org?node_id=1089172


in reply to Faster way to regex this

Have you tried using a character class?

$dir =~ s/([\[\]{}~*?])/\\$1/g;

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Re^2: Faster way to regex this
by AnomalousMonk (Archbishop) on Jun 08, 2014 at 11:04 UTC

    A look-ahead might be faster, but this still doesn't address the question of  \ (backslash) handling raised by Corion below.

    c:\@Work\Perl\monks>perl -wMstrict -le "my $s = 'foo\bar\[baz[x]x{x}x~x*x?x[]{}~*?'; print qq{'$s'}; ;; $s =~ s{ (?= [][{}~*?]) }{\\}xmsg; print qq{'$s'}; " 'foo\bar\[baz[x]x{x}x~x*x?x[]{}~*?' 'foo\bar\\[baz\[x\]x\{x\}x\~x\*x\?x\[\]\{\}\~\*\?'