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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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User Contributed Notes 4 notes

down

ClayDragon ¶

5 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

down

Anonymous ¶

11 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.

down

harry at upmind dot com ¶

2 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);
    }
?>

down

Kalahiri ¶

9 months ago

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

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