echo json_encode(true); // string "true"
echo json_encode(false); // string "false"
// null !== false
echo json_encode(null); // string "null"/**
* Strings always evaluate to boolean true unless they have a
* value that's considered "empty" by PHP (taken from the
* documentation for empty):
* "" (an empty string) evaluates as false.
* "0" (0 as a string) evaulates as false.
* If you need to set a boolean based on the text value of a
* string, then you'll need to check for the presence or
* otherwise of that value.
*/
$boolean = $string === 'true' ? true: false;$converted_res = $res ? 'true' : 'false';// (PHP 5 >= 5.5.0, PHP 7)
// boolval — Get the boolean value of a variable
boolval ( mixed $var ) : bool
// Returns the boolean value of var.