From: Robert Klemme <shortcutter@...>
Date: 2009-11-27T21:57:51+09:00
Subject: Re: Pattern match to fail if two periods in a row

2009/11/27 Aldric Giacomoni <aldric@trevoke.net>:
> Ralph Shnelvar wrote:
>> How does one create an expression that fails if there are two or more
>> periods
>> (e.g. "..") in a row?
>
> As previously mentioned, you can use this:
> /\.{2,}/

That only positively matches strings which contain at least two dots
in a row.  OP specifically wanted to _not_ have a match for two dots
in a row.

> You can also use this:
> /[..+]/

Did you test that?  How should this expression match two dots in a
row?  You have define a character class with "." and "+" where one dot
is redundant.

irb(main):001:0> /[..+]/ =~ "+"
=> 0
irb(main):002:0> /[..+]/ =~ "."
=> 0

> On the other hand, if you are looking to validate an email address,
> there are already rails plugins that do that (and more) - so why
> reinvent the wheel? :)

If he's reinventing the wheel then that's certainly not a good idea.
I just guess that you are talking about a different wheel. :-)

Kind regards

robert


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