vertito wrote: > /[\s']((mountain.*clouds)|(clouds.*mountain))[\s',-]/i > > great, the above works on making "mountain" and "clouds" both true. > > does the below differs from the above? > > /\bmountain\b|\bclouds\b/i >
Absolutely. That second string is an OR operation. It will match mountain, OR clouds, and requires a "word boundary" at the beginning and end. You need a whitespace, punctuation mark, or end/beginning of string. ie: it won't match "cloudspray" or "airmountain", but will match "mountain, " or "-clouds". It's actually quite similar to how your CF_BAD_SUBJ12 would work if you removed the errant \ in front of the |. However, there are some subtle differences in what boundaries this rule will accept. It requires a specific set of possible boundaries, and isn't zero-width so it won't match anything starting with "mountain" or "clouds". Really in regexes there is no such thing as an AND operation. It's just not something natural to do in a regex. So in the first chunk, John faked an And. What you really have is two expressions that are ORed together. (mountain.*clouds) will match anything containing mountain, followed by clouds, with any number of characters in between them (.*). (clouds.*mountain) will look for clouds first.. By ORing the two together, you've got the equivalent of an AND, because it will match anything containing both words, no matter which order they come in.
