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    ctype_alnum

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

    ctype_alnum — 英数字かどうかを調べる

    説明

    ctype_alnum(mixed $text): bool

    与えられた文字列 text のすべての文字が英字または 数字であるかどうかを調べます。

    パラメータ

    text

    調べる文字列。

    注意:

    -128 から 255 までの int を渡すと、ひとつの文字の ASCII 値とみなします (負の値には 256 を足して、拡張 ASCII の範囲に収まるようにします)。 それ以外の整数値は、10 進数を含む文字列とみなします。

    警告

    PHP 8.1.0 以降は、ctype関数 に文字列でない引数を渡すことは、推奨されなくなりました。将来のバージョンでは、引数は ASCII コードポイントではなく、文字列として解釈されるようになります。ユーザが意図する振る舞いによっては、引数を文字列にキャストするか、 chr() を明示的にコールすべきです。

    戻り値

    text のすべての文字が英字または数字だった場合に true 、そうでない場合に false を返します。 空文字列を渡して呼び出した場合、結果は常に false になります。

    例

    例1 A ctype_alnum() の例 (デフォルトのロケールを使用)

    <?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";
    }
    }
    ?>

    上の例の出力は以下となります。

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

    参考

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    User Contributed Notes 4 notes

    up
    97
    thinice at gmail dot com
    16 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.';
}
?>
    up
    11
    marcelocamargo at linuxmail dot org
    10 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)
    up
    23
    Anonymous
    13 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).
    up
    0
    luismartin at casfid dot com
    20 hours ago
    Be aware that this function will not validate non-english alphanumeric characters. Only ASCII.

<?php
$test = "aeiou";
echo ctype_alnum($test) ? "ok\n" : "err\n";
$test = "áeiou";
echo ctype_alnum($test) ? "ok\n" : "err\n";
$test = "aeiöu";
echo ctype_alnum($test) ? "ok\n" : "err\n";
$test = "ñ";
echo ctype_alnum($test) ? "ok\n" : "err\n";

// output:
// ok
// err
// err
// err
?>

In case you want to validate these types of characters, the best choice is the use of regex, but there's a shortcut so that you will not have to bother typing all of them:

This regex: /^[\p{L}\p{M}\p{Nd}]+$/u
\p{L}  = Any letter, syllable, or ideogram from any Unicode script.
\p{M}  = Any combining mark (necessary for vowels/accents in languages like Arabic or Hindi).
\p{Nd} = Any decimal digit (0-9) from any script, excluding fractions like ½ or Roman numerals.
u = The modifier at the end says: treat the string as a UTF-8 representation.

<?php
$test = "aeiouáöñçسअ爱";
echo preg_match('/^[\p{L}\p{M}\p{Nd}]+$/u', $test) ? "ok\n" : "err\n";
$test = "aeiouáöñçسअ爱!+½";
echo preg_match('/^[\p{L}\p{M}\p{Nd}]+$/u', $test) ? "ok\n" : "err\n";

// output:
// ok
// err
?>
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