ctype_print
(PHP 4 >= 4.0.4, PHP 5)
ctype_print — Check for printable character(s)
Description
$text
)
Checks if all of the characters in the provided string,
text, are printable.
Parameters
-
text -
The tested string.
Return Values
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.
Examples
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";
}
}
?>
The above example will output:
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.
Notes
Note:
If an integer between -128 and 255 inclusive is provided, it is interpreted as the ASCII value of a single character (negative values have 256 added in order to allow characters in the Extended ASCII range). Any other integer is interpreted as a string containing the decimal digits of the integer.
See Also
- 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
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 );