ctype_print
(PHP 4 >= 4.0.4, PHP 5)
ctype_print — Check for printable character(s)
Описание
bool ctype_print
( string $text
)
Checks if all of the characters in the provided string, text , are printable.
Список параметров
- text
-
The tested string.
Возвращаемые значения
Returns TRUE if every character in text will actually create output (including blanks). Returns FALSE if text contains control characters or characters that do not have any output or control function at all.
Примеры
Пример #1 A ctype_print() example
<?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";
}
}
?>
Результат выполнения данного примера:
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.
Коментарии
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.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
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);
}
?>
To check whether a string consists only of ASCII characters, use mb_detect_encoding( $string, 'ASCII', true );