ctype_print

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

ctype_print — 检测可打印字符

说明

ctype_print(mixed $text): bool

检测提供的 string 类型的 text 里面的所有字符是否都可打印。

参数

text

要测试的字符串。

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.

警告

自 PHP 8.1.0 起，弃用传递非字符串参数。未来该参数将解释为字符串而不是 ASCII 码点。根据预期行为，应将参数转为字符串或显式调用 chr()。

返回值

如果在当前的语言环境下 text 里面的每个字符都能被实际输出（包括空白），那么就返回 true；如果 text 包含控制字符或者没有任何输出的字符，那么就返回 false。当使用空字符串调用时，结果始终为 false。

示例

示例 #1 ctype_print() 示例

<?php
$strings = array('string1' => "asdf\n\r\t", 'string2' => 'arf12', 'string3' => 'LKA#@%.54');
foreach ($strings as $name => $testcase) {
    if (ctype_print($testcase)) {
        echo "The string '$name' consists of all printable characters.\n";
    } else {
        echo "The string '$name' does not consist of all printable characters.\n";
    }
}
?>

以上示例会输出：

The string 'string1' does not consist of all printable characters.
The string 'string2' consists of all printable characters.
The string 'string3' consists of all printable characters.

参见

ctype_cntrl() - 检测控制字符
ctype_graph() - 检测除空格外的任何打印字符
ctype_punct() - 检测可打印的字符是不是不包含空白、数字和字母
IntlChar::isprint() - Check if code point is a printable character

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用户贡献的备注 4 notes

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ClayDragon ¶

6 years ago

As mentioned above, only ASCII characters from 32 to 126 are considered printable, all others, including UTF-8 encoded characters are always considered unprintable, no matter what your locale settings are. Therefore, e.g. German "ä", the Euro sign "€" or the British pound symbol "£" will never be printable. If you need to check any characters for "printability" beyond the standard ASCII range, use a regular expression or write a specific function yourself.

See also this discussion: https://grokbase.com/t/php/php-i18n/102tkqe6rk/ctype-print-returns-false-for-british-pound-symbol-and-non-ascii-symbols

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Anonymous ¶

12 years ago

Only ascii 32 thru 126 (inclusive) are considered printable. Tab (ascii 7), carriage return (ascii 13), linefeed (ascii 10) etc may produce output but are not considered printable.

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harry at upmind dot com ¶

3 years ago

You can use this function to detect if a string is "binary".

<?php
    /**
     * Determine whether the given value is a binary string by checking to see if it contains only printable characters.
     *
     * @param string $value
     *
     * @return bool
     */
    function isBinary($value): bool
    {
        // remove "unprintable" whitespace characters (tabs, newlines etc)
        $string = preg_replace('/\s/', '', (string)$value);

        return !empty($string) && !ctype_print($string);
    }
?>

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Kalahiri ¶

1 year ago

To check whether a string consists only of ASCII characters, use mb_detect_encoding( $string, 'ASCII', true );