ctype_xdigit()
(PHP 4 >= 4.0.4, PHP 5, PHP 7)
检测字符串是否只包含十六进制字符
说明
ctype_xdigit(string $text): bool
检查string和$text里面的字符是不是都是十六进制字符串。
参数
- $text
需要被测试的字符串。
返回值
如果$text里面的每个字符都是十六进制字符。也就是只能包含十进制的树枝和[A-Fa-f]的字母。否则,返回FALSE
。
范例
一个ctype_xdigit()的例子
<?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 $testcase does not consist of all hexadecimal digits.\n"; } } ?>
以上例程会输出:
The string AB10BC99 consists of all hexadecimal digits. The string AR1012 does not consist of all hexadecimal digits. The string ab12bc99 consists of all hexadecimal digits.
注释
Note:如果给出一个-128 到 255 之间(含)的整数,将会被解释为该值对应的ASCII字符(负值将加上 256 以支持扩展ASCII字符).其它整数将会被解释为该值对应的十进制字符串.
参见
ctype_digit()
做纯数字检测
This function shows its usefulness on a web site where a user is asked to entered a hexidecimal color code for a color. To prevent breaking W3C standard and having them enter in "neon-green" or the wrong type of code like 355511235. In conjunction with strlen() you could create a function like this: function check_valid_colorhex($colorCode) { // If user accidentally passed along the # sign, strip it off $colorCode = ltrim($colorCode, '#'); if ( ctype_xdigit($colorCode) && (strlen($colorCode) == 6 || strlen($colorCode) == 3)) return true; else return false; }