preg_match exclude a number

I have this code

preg_match("/\bHTTP(.)+ (\d{3})/", $string)

In the last pattern I have to check for a 3 digit number that can be compo开发者_JAVA技巧sed by any digit but should not create a number like 404 or 401, how can I do it?

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You can use the negative lookahead assertion to ensure that the matched string does not have a 404 or a 401 as:

preg_match("/\bHTTP(.+) (?!404|401)(\d{3})/", $string)

Rubular Link

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The more values you want to exclude, the more complicated this will get, but

preg_match("/\bHTTP(.+) ([0-35-9]\d{2}|4[1-9]\d|40[0235-9])/", $string)

will match any three digit number that doesn't start with 4,

or any three digit number that starts with 4 but doesn't start with 40,

or any three digit number that starts with 40 but isn't 401 or 404.

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explanation:

A negative lookahead ?! looks for text that does not match the specified pattern. A positive lookahead looks for a pattern to match but not to return.

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

• ?! do not match the following pattern
• 404|401 either 404 or 401, so the | is used for alternatives