Re: Make a variable safe for a regex.

Quote everything that could be a metacharacter before using the variable: s/(\W)/\\$1/g

There's also quotemeta, but I've been using the above pattern for years.

Comment on Re: Make a variable safe for a regex. Download Code

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Re^2: Make a variable safe for a regex. by Anno (Deacon) on Feb 25, 2007 at 22:55 UTC
Well, they appear to do the same, at least in the one-byte character range: `my $str = join '', map chr, 0 .. 255; my $qm = quotemeta( $str); ( my $kyle = $str) =~ s/(\W)/\\$1/g; my $quoted_qm = join '', $qm =~ /\\(.)/g; my $quoted_kyle = join '', $kyle =~ /\\(.)/g; printf "quotemeta: %d, kyle: %d (%s)\n", length $quoted_qm, length $quoted_kyle, $quoted_qm eq $quoted_kyle ? "same" : "differernt";` [download] That prints `quotemeta: 192, kyle: 192 (same)` [download] Anno	[reply] [d/l] [select]
Re^3: Make a variable safe for a regex. by diotalevi (Canon) on Feb 26, 2007 at 00:47 UTC
\Q and quotemeta() are the same function. ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊	[reply]
Re^4: Make a variable safe for a regex. by Anno (Deacon) on Feb 26, 2007 at 08:32 UTC
True, but kyle's alternative (which I compared with quotemeta) isn't based on \Q. Anno	[reply]