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Check if has only letters, numbers and underscore

Posted on 2006-07-14
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Last Modified: 2008-09-09
What is the reg exp syntax for checking if a string has only letters, numbers and underscore in it?

thanks
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Question by:blacklord
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Roonaan earned 250 total points
ID: 17106294
if(preg_match('/^\w+$/',$string)) {
  //string not empty and requested chars only
}

-r-
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by:Richard Quadling
ID: 17106730
NOTE!

A "word" character is any letter or digit or the underscore character, that is, any character which can be part of a Perl "word". The definition of letters and digits is controlled by PCRE's character tables, and may vary if locale-specific matching is taking place. For example, in the "fr" (French) locale, some character codes greater than 128 are used for accented letters, and these are matched by \w.

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