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Re: regex question


From: Barry Margolin
Subject: Re: regex question
Date: Mon, 19 May 2003 19:07:09 GMT

In article <address@hidden>, upro  <address@hidden> wrote:
>This might be a stupid question:
>
>I want to use M-x replace-regexp like this
>
>s/[a-z]''/$1"/g
>
>the first part [a-z]'' works, but then the mathed lowercase letter is
>not reinserted, but a litteral $1.

If you want to grab a part of the matched text, you should use \<digit>,
etc.; $<digit> is Perl's equivalent, but most other regexp packages use
\<digit>.

Also, you need to put parentheses around the part that you want it to
remember.  So it should be:

Old: \([a-z]\)''
New: \1"

>How does that work in emacs-regex? I don't find the relevant info in
>the info file...

File: emacs,  Node: Regexp Replace

Regexp Replacement
------------------

   The `M-x replace-string' command replaces exact matches for a single
string.  The similar command `M-x replace-regexp' replaces any match
for a specified pattern.

   In `replace-regexp', the NEWSTRING need not be constant: it can
refer to all or part of what is matched by the REGEXP.  `\&' in
NEWSTRING stands for the entire match being replaced.  `\D' in
NEWSTRING, where D is a digit, stands for whatever matched the Dth
parenthesized grouping in REGEXP.  To include a `\' in the text to
replace with, you must enter `\\'.  For example,

-- 
Barry Margolin, address@hidden
Genuity Managed Services, a Level(3) Company, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.


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