From: John Joyce <dangerwillrobinsondanger@...>
Date: 2007-08-03T05:25:40+09:00
Subject: Re: RegEx for punctuation?


On Aug 2, 2007, at 2:26 PM, John Joyce wrote:

>
> On Aug 2, 2007, at 2:14 PM, Alex Young wrote:
>
>> John Joyce wrote:
>>> Hey all,
>>> I have a quick question about RegEx, which I don't use often and  
>>> I don't have my reference book handy.
>>> How do I gsub all non alpha-numeric characters to nothing,
>>> I know it's something like this:
>>> some_string.gsub!('something here', '')
>> irb(main):002:0> ",.'abc123".gsub(/[^[:alnum:]]/, '')
>> => "abc123"
>>
>> -- 
>> Alex
>>
> Thanks a million!
> I'm going to have to do more RegEx stuff to get it buried into my  
> brain!
>
> One more question though, I previously had this to turn spaces into  
> underscores
> some_string.gsub(' ','')
>
> How can do this while removing all non-space characters?
>
> John Joyce
>
>
>
Found it. In Peter Cooper's book! (I knew I bought that ebook for a  
reason)
this is my final version:

     @asset.permalink = @asset.name.downcase.gsub(' ', '_').gsub(/ 
\W/,'')

downcase everything, turn spaces into underscores, then take all non- 
alpha/non-numeric/non-underscore characters out.
sweet and simple.
For anyone else looking for it in the archives,
\w  matches all alpha/numeric/underscore characters
\W matches everything else.

I could go a little further in the case of something like

title = 'Untitled #234'

and do this:

title = title.downcase.gsub(' ', '_').gsub('#', 'number').gsub(/\W/, '')

resulting in:
untitled_number234

Nice and tidy. Could be a bit further refined to make sure a space is  
prepended to 'number' if no space precedes '#' and to make sure a  
number actually follows '#' in before going to all the trouble.
If I wanted hard to read, I could even try to squeeze it all into one  
big RegEx, but the thing I've got above will suffice for now.

cheers,
John Joyce