RE: [PHP] Regex help

Bret Hughes wrote: > On Sat, 2005-01-29 at 08:58, Michael Sims wrote: >> kjohnson@zootweb.com wrote: >>> I need a validation regex that will "pass" a string. The string can >>> be no longer than some maximum length, and it can contain any >>> characters except two consecutive ampersands (&) anywhere in the >>> string. >>> >>> I'm stumped - ideas? >> >> Yup, use this perl regex: >> >> /^(?:(&)(?!&)|[^&]){1,5}$/ > > Great explanation. Thanks from one who has not had an exam for over > ten years. Thanks...I actually just realized that the parentheses around the first ampersand are unnecessary (that was a leftover from a previous attempt), so this is simpler and will work just as well: /^(?:&(?!&)|[^&]){1,5}$/ Or if you don't care about capturing portions of the match and then throwing them away: /^(&(?!&)|[^&]){1,5}$/