(PHP 4 >= 4.0.4, PHP 5)
ctype_xdigit — Check for character(s) representing a hexadecimal digit
$text
)
Checks if all of the characters in the provided string,
text, are hexadecimal 'digits'.
text
The tested string.
Returns TRUE if every character in text is
a hexadecimal 'digit', that is a decimal digit or a character from
[A-Fa-f] , FALSE otherwise.
Example #1 A ctype_xdigit() example
<?php
$strings = array('AB10BC99', 'AR1012', 'ab12bc99');
foreach ($strings as $testcase) {
if (ctype_xdigit($testcase)) {
echo "The string $testcase consists of all hexadecimal digits.\n";
} else {
echo "The string $testcase does not consist of all hexadecimal digits.\n";
}
}
?>
以上例程会输出：
The string AB10BC99 consists of all hexadecimal digits. The string AR1012 does not consist of all hexadecimal digits. The string ab12bc99 consists of all hexadecimal digits.
Note:
如果给出一个 -128 到 255 之间(含)的整数, 将会被解释为该值对应的ASCII字符 (负值将加上 256 以支持扩展ASCII字符). 其它整数将会被解释为该值对应的十进制字符串.