PHP - Manual: ctype_alnum

2024-05-05

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ctype_alnum

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

ctype_alnum — 做字母和数字字符检测

说明

ctype_alnum(string $text): bool

检查提供的string,text 是否全部为字母和(或)数字字符。

参数

text: 测试字符串。

返回值

如果text中所有的字符全部是字母和(或者)数字，返回 true 否则返回false

范例

示例 #1 A ctype_alnum() 示例 (使用默认的区域设置)


<?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";
    }
}
?>

以上例程会输出：

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

注释

注意:
如果给出一个 -128 到 255 之间(含)的int, 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_alpha() - 做纯字符检测
ctype_digit() - 做纯数字检测
setlocale() - 设置地区信息

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User Contributed Notes 4 notes

down

thinice at gmail dot com ¶

12 years ago


ctype_alnum() is a godsend for quick and easy username/data filtering when used in conjunction with str_replace().


Let's say your usernames have dash(-) and underscore(_) allowable and alphanumeric digits as well.


Instead of a regex you can trade a bit of performance for simplicity:


<?php

$sUser = 'my_username01';

$aValid = array('-', '_');


if(!ctype_alnum(str_replace($aValid, '', $sUser))) {

    echo 'Your username is not properly formatted.';

}

?>

down

marcelocamargo at linuxmail dot org ¶

6 years ago


It is also important to note that the behavior of `ctype_alnum` differs according to the operating system. For UNIX-based operating system, if you pass a value that is not a string (or an overloaded object), independently of the value, it will always result in false. However, if we do the same on Windows, using, for example, -1 as literal (a minus and a number greater than 0), we'll have true as result.

<?php var_dump(ctype_alnum(-1));
// UNIX: bool(false)
// Windows: bool(true)

down

Anonymous ¶

9 years ago


Quicktip: If ctype is not enabled by default on your server, replace ctype_alnum($var) with preg_match('/^[a-zA-Z0-9]+$/', $var).

down

-10

Rory ¶

12 years ago


Just for the record, Gentoo doesn't include this function by default. You'll have to recompile PHP with the "ctype" USE flag.

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官方地址：https://www.php.net/manual/en/function.ctype-alnum.php

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PHP官方手册 - 互联网笔记

ctype_alnum

说明

参数

返回值

范例

注释

参见

User Contributed Notes 4 notes