regex question: independent position of words

is it possible to define a regex pattern which checks eg. for 3 terms independent to their position in the ma开发者_Go百科in string?

eg. my string is something like "click here to unsubscribe: http://www.url.com"

the pattern should also work with "http:// unsubscribe click"

thx

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You can use positive lookaheads. For example,

(?=.*click)(?=.*unsubscribe).*http

is a regex that will look ahead from the current position (without moving ahead) for click, then for unsubscribe, then search normally for http.

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It's possible, but results in very complicated regexs, e.g.:

/(click.*unsubscribe|unsubscribe.*click)/

Basically, you would need to have a different regex section for each order. Not ideal. Better to just use multiple regexes, one for each term.

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Yes, using conditionals.

http://www.regular-expressions.info/conditional.html