ctype_cntrl - PHP code example

The php Function Ctype_Cntrl

The php function ctype_cntrl is used to check if the string/text contains any control characters. It is an inbuilt function that is available in the ctype extension in PHP. It accepts a string as input parameter and returns a boolean value.

The function ctype_cntrl() checks if the string contains any control characters like line feed, tab and escape. It is similar to the isdigit() function but it returns true even if the string has a hexadecimal digit (like 123 or 1e3), while isdigit() only gives you false for such strings.

Other functions in the ctype extension offer a wide range of checking, such as ctype_alpha() which checks for alphabetical characters from A to Z, ctype_digit() which checks for numeric characters (0-9), ctype_graph() which checks for visually printable characters and ctype_upper() and ctype_lower() which verify if the string is upper or lower case. Combined with these and other validation functions, developers can create powerful filtering and verification rules for their applications.

In the end:

A solid understanding of character type validation and other essential php skills is crucial for the success of any web development project. Knowing how to use these functions will help you build secure and reliable applications that can withstand attacks from malicious users. Make sure you have a strong grasp of these and other relevant php knowledge before heading into the next interview, to boost your chances of landing that dream job!

ctype_cntrl example

use Symfony\Polyfill\Ctype as p;

if (!function_exists('ctype_alnum')) {
    function ctype_alnum(mixed $text): bool { return p\Ctype::ctype_alnum($text); }
}
if (!function_exists('ctype_alpha')) {
    function ctype_alpha(mixed $text): bool { return p\Ctype::ctype_alpha($text); }
}
if (!function_exists('ctype_cntrl')) {
    function ctype_cntrl(mixed $text): bool { return p\Ctype::ctype_cntrl($text); }
}
if (!function_exists('ctype_digit')) {
    function ctype_digit(mixed $text): bool { return p\Ctype::ctype_digit($text); }
}
if (!function_exists('ctype_graph')) {
    function ctype_graph(mixed $text): bool { return p\Ctype::ctype_graph($text); }
}
if (!function_exists('ctype_lower')) {
    function ctype_lower(mixed $text): bool { return p\Ctype::ctype_lower($text); }
}
if (!function_exists('ctype_print')) {

if (\PHP_VERSION_ID >= 80000) {
    return require __DIR__.'/bootstrap80.php';
}

if (!function_exists('ctype_alnum')) {
    function ctype_alnum($text) { return p\Ctype::ctype_alnum($text); }
}
if (!function_exists('ctype_alpha')) {
    function ctype_alpha($text) { return p\Ctype::ctype_alpha($text); }
}
if (!function_exists('ctype_cntrl')) {
    function ctype_cntrl($text) { return p\Ctype::ctype_cntrl($text); }
}
if (!function_exists('ctype_digit')) {
    function ctype_digit($text) { return p\Ctype::ctype_digit($text); }
}
if (!function_exists('ctype_graph')) {
    function ctype_graph($text) { return p\Ctype::ctype_graph($text); }
}
if (!function_exists('ctype_lower')) {
    function ctype_lower($text) { return p\Ctype::ctype_lower($text); }
}
if (!function_exists('ctype_print')) {