Regular expression match

Regular expression match

[Qiang]

Hi

I am trying to use regular expression in Emacs. And I have
question about how to return the matched item. For example,
I want to match and return '8' in the string 'Vol.8'. How
can I achieve that ?

Thanks

Re: Regular expression match

[Pascal J. Bourguignon]

Qiang <mcknight0219@gmail.com> writes:

> Hi
>
> I am trying to use regular expression in Emacs. And I have
> question about how to return the matched item. For example,
> I want to match and return '8' in the string 'Vol.8'. How
> can I achieve that ?

Using groups and match-string.  For example:

(when (re-search-forward "Vol.\(8\)")
   (match-string 1))

-- 
__Pascal Bourguignon__

Re: Regular expression match

[Kevin Rodgers]

Pascal J. Bourguignon wrote:
> Qiang <mcknight0219@gmail.com> writes:
> 
>> Hi
>>
>> I am trying to use regular expression in Emacs. And I have
>> question about how to return the matched item. For example,
>> I want to match and return '8' in the string 'Vol.8'. How
>> can I achieve that ?
> 
> Using groups and match-string.  For example:
> 
> (when (re-search-forward "Vol.\(8\)")
>    (match-string 1))

The regexp string should be "Vol\\.\\(8\\)"

-- 
Kevin Rodgers
Denver, Colorado, USA

RE: Regular expression match

[Timothy Schaeffer]

> Pascal J. Bourguignon wrote:
> > Qiang <mcknight0219@gmail.com> writes:
> > 
> >> I am trying to use regular expression in Emacs. And I have question 
> > Using groups and match-string.  For example:
> > 
> > (when (re-search-forward "Vol.\(8\)")
> >    (match-string 1))
> 
> The regexp string should be "Vol\\.\\(8\\)"

And you can avoid emacs' regexp-in-strings hyperquoting with the rx macro.

(rx "Vol." (group "8")) = "Vol\\.\\(8\\)"

Tim S

Re: Regular expression match

[Pascal J. Bourguignon]

Kevin Rodgers <kevin.d.rodgers@gmail.com> writes:

> Pascal J. Bourguignon wrote:
>> Qiang <mcknight0219@gmail.com> writes:
>> 
>>> Hi
>>>
>>> I am trying to use regular expression in Emacs. And I have
>>> question about how to return the matched item. For example,
>>> I want to match and return '8' in the string 'Vol.8'. How
>>> can I achieve that ?
>> Using groups and match-string.  For example:
>> (when (re-search-forward "Vol.\(8\)")
>>    (match-string 1))
>
> The regexp string should be "Vol\\.\\(8\\)"

Of course.  Sorry.

-- 
__Pascal Bourguignon__