How to convert PascalCase to pascal_case?

Question

If I had:

$string = \"PascalCase\";

I need

\"pascal_case\"

Does PHP offer a function for this purpose?

Answer 1

Laravel 5.6 provides a very simple way of doing this:

 /**
 * Convert a string to snake case.
 *
 * @param  string  $value
 * @param  string  $delimiter
 * @return string
 */
public static function snake($value, $delimiter = '_'): string
{
    if (!ctype_lower($value)) {
        $value = strtolower(preg_replace('/(.)(?=[A-Z])/u', '$1'.$delimiter, $value));
    }

    return $value;
}

What it does: if it sees that there is at least one capital letter in the given string, it uses a positive lookahead to search for any character (.) followed by a capital letter ((?=[A-Z])). It then replaces the found character with it's value followed by the separactor _.