Check for alphanumeric character(s)

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- Check for alphanumeric character(s)

# ctype_alnum

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

ctype_alnum — Check for alphanumeric character(s)

### Description

ctype_alnum(mixed `$text`): bool

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

### Parameters

`text`

  The tested string.

  > Note:

  > If an int 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.

  Warning

  As of PHP 8.1.0, passing a non-string argument is deprecated. In the future, the argument will be interpreted as a string instead of an ASCII codepoint. Depending on the intended behavior, the argument should either be cast to string or an explicit call to chr() should be made.

### Return Values

Returns `true` if every character in `text` is either a letter or a digit, `false` otherwise. When called with an empty string the result will always be `false`.

### Examples

Example #1 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.

### See Also

- ctype_alpha() - Check for alphabetic character(s)
- ctype_digit() - Check for numeric character(s)
- setlocale() - Set locale information
- IntlChar::isalnum() - Check if code point is an alphanumeric character