PHP : Function Reference : Character Type Functions : ctype_alnum PHP Examples Tutorials References

Example 416. A ctype_alnum() example (using the default locale)

<?php

$strings = array('AbCd1zyZ9', 'foo!#$bar');

foreach ($strings as $testcase) {

    if (ctype_alnum($testcase)) {

        echo "The string $testcase consists of all letters or digits.\n";

    } else {

        echo "The string $testcase does not consist of all letters or digits.\n";

    }

}
?>

The above example will output:

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The string AbCd1zyZ9 consists of all letters or digits.

The string foo!#$bar does not consist of all letters or digits.

Code Examples / Notes » ctype_alnum

When checking strings with multiple words for non alphanumeric characters ctype_alnum would consider space as non alphanumeric character as well. So to check a string with multiple words for non alphanumeric characters use str_replace foreach ($imported_queries as $check_aplhanum) { $check_aplhanum = str_replace (" ", "", $check_aplhanum); if (!(ctype_alnum($check_aplhanum))) { echo "Query string contains alphanumeric characters"; } }

Caution: ctype_alnum() will return false on integers. <?php var_dump(ctype_alnum('3')); // true var_dump(ctype_alnum(3)); // false ?> See http://bugs.php.net/bug.php?id=42007 .

Although in an empty string "every character is either a letter or a digit", ctype_alnum('') will return bool(false)! Please try at home :-) For now, I use: if($input !== '' && !ctype_alnum($input)) throw new Exception('Invalid input'); Somebody better suggestions? (except preg_match)

ctype_alnum

Check for alphanumeric character(s) (PHP 4 >= 4.0.4, PHP 5)
bool ctype_alnum ( string text )

Example 416. A ctype_alnum() example (using the default locale)

Code Examples / Notes » ctype_alnum

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ctype_alnum

Check for alphanumeric character(s) (PHP 4 >= 4.0.4, PHP 5) bool ctype_alnum ( string text )

Example 416. A ctype_alnum() example (using the default locale)

Code Examples / Notes » ctype_alnum

Change Language

Check for alphanumeric character(s) (PHP 4 >= 4.0.4, PHP 5)
bool ctype_alnum ( string text )