How can I check that a data value is alphanumeric?

There are various ways to do this, and people commonly do this with a regular expression of some description.

However if you don't want to get involved with those or find them confusing, as usual with PHP there is a function lurking around to help you achieve your desired result.

You can easily validate specific to the curernt locale setting with the ctype_alpha function, one of the character type functions added to PHP in version 4.3 which works like this:


<?php

$formvalue = "am I alphanumeric or not";

if(ctype_alpha($formvalue)) { echo "Yes I am!"; } else { echo "No I'm not!"; }

?>

In this case printing "No I'm not!" because $formvalue contains spaces.

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