Ctype Functions
PHP Manual


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

ctype_alnumCheck for alphanumeric character(s)


bool ctype_alnum ( string $text )

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



The tested string.

Return Values

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


Example #1 A ctype_alnum() example (using the default locale)

= array('AbCd1zyZ9''foo!#$bar');
foreach (
$strings as $testcase) {
    if (
ctype_alnum($testcase)) {
"The string $testcase consists of all letters or digits.\n";
    } else {
"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.



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.

See Also

Ctype Functions
PHP Manual