ctype_alnum

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

Check for alphanumeric character(s)

bool ctype_alnum ( string $text )

Checks if all of the characters in the provided string, text, are alphanumeric.

Parameters:

text

The tested string.

Returns:

Returns TRUE if every character in text is either a letter or a digit, FALSE otherwise.

Notes:

If an integer between -128 and 255 inclusive is provided, it is interpreted as the ASCII value of a single character (negative values have 256 added in order to allow characters in the Extended ASCII range). Any other integer is interpreted as a string containing the decimal digits of the integer.

Examples:

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:

The string AbCd1zyZ9 consists of all letters or digits.
The string foo!#$bar does not consist of all letters or digits.