mdgArt » regexp http://www.mdgart.com Art & Programming Thu, 12 Jan 2012 11:56:28 +0000 http://wordpress.org/?v=2.8.5 en hourly 1 RegEx: Link not beginning with http:// http://www.mdgart.com/2009/01/23/regex-link-not-beginning-with-http/ http://www.mdgart.com/2009/01/23/regex-link-not-beginning-with-http/#comments Fri, 23 Jan 2009 16:54:01 +0000 Mauro http://www.mdgart.com/?p=3 I had to find a regex to match not a string that contain something, but a string that not contain something, and in particular i had to check that a link entered in a form does not begin with http://. I needed to use a regex for this that work with PHP and, i have to admin, it was not so simple.
The method that i found is based on lookahead technique, but seem to work only with preg_match() and not with ereg(). Is not perfect, because it don’t match any string that contain http://, not only that begin with.
This is the regex:


(^((?!.*http\://).)*$)

This match www.ciao.com, but not http://www.ciao.com and also not www.ciao.com/http:// and any string that contain http://. It work for my needs, but is not what really wanted to achieve.
If you know a method to correct the regex, please tell me.

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