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
ctype_print
(PHP 4 >= 4.0.4, PHP 5, PHP 7)
ctype_print — Check for printable character(s)
설명
bool ctype_print
( string
$text
)
Checks if all of the characters in the provided string,
text, are printable.
인수
-
text -
The tested string.
반환값
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.
예제
Example #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";
}
}
?>
위 예제의 출력:
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.
주의
Note:
-128이상 255이하의 integer를 지정할 경우, 한 문자의 ASCII 값으로 해석합니다. (음수는 256이 더해져 확장 ASCII 영역의 문자가 됩니다) 그 외의 정수는 그 정수를 표현하는 10진 문자열로 해석합니다.
참고
- ctype_cntrl() - Check for control character(s)
- ctype_graph() - Check for any printable character(s) except space
- ctype_punct() - Check for any printable character which is not whitespace or an alphanumeric character
add a note
User Contributed Notes 4 notes
ClayDragon ¶
6 years ago
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.
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);
}
?>
