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ctype_alnum

(PHP 4 >= 4.0.4, PHP 5)

ctype_alnum -- Check for alphanumeric character(s)

说明

bool ctype_alnum ( string text )

Checks if all of the characters in the provided string, text, are alphanumeric. In the standard C locale letters are just [A-Za-z] and the function is equivalent to preg_match('/^[a-z0-9]*$/i', $text).

参数

text

The tested string.

返回值

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

范例

例子 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";
    }
}
?>

上例将输出：

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

参见

ctype_alpha()
ctype_digit()
setlocale()


add a note add a note User Contributed Notes
mail at fredemmott dot co dot uk
27-May-2006 08:26
The 'equivalent' preg_match given here is not truly equivalent. If the variable is null or the empty string, the results differ.
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