Change 20997 by [EMAIL PROTECTED] on 2003/09/02 14:58:21
Subject: [PATCH perlfaq6.pod] Explain \Q better
From: Mark Jason Dominus <[EMAIL PROTECTED]>
Date: Mon, 01 Sep 2003 16:19:20 -0400
Message-ID: <[EMAIL PROTECTED]>
Affected files ...
... //depot/perl/pod/perlfaq6.pod#42 edit
Differences ...
==== //depot/perl/pod/perlfaq6.pod#42 (text) ====
Index: perl/pod/perlfaq6.pod
--- perl/pod/perlfaq6.pod#41~18459~ Wed Jan 8 12:48:19 2003
+++ perl/pod/perlfaq6.pod Tue Sep 2 07:58:21 2003
@@ -292,14 +292,26 @@
also that any regex special characters will be acted on unless you
precede the substitution with \Q. Here's an example:
- $string = "to die?";
- $lhs = "die?";
- $rhs = "sleep, no more";
+ $string = "Placido P. Octopus";
+ $regex = "P.";
- $string =~ s/\Q$lhs/$rhs/;
- # $string is now "to sleep no more"
+ $string =~ s/$regex/Polyp/;
+ # $string is now "Polypacido P. Octopus"
-Without the \Q, the regex would also spuriously match "di".
+Because C<.> is special in regular expressions, and can match any
+single character, the regex C<P.> here has matched the <Pl> in the
+original string.
+
+To escape the special meaning of C<.>, we use C<\Q>:
+
+ $string = "Placido P. Octopus";
+ $regex = "P.";
+
+ $string =~ s/\Q$regex/Polyp/;
+ # $string is now "Placido Polyp Octopus"
+
+The use of C<\Q> causes the <.> in the regex to be treated as a
+regular character, so that C<P.> matches a C<P> followed by a dot.
=head2 What is C</o> really for?
End of Patch.
