boolval('false');
filter_var( true, FILTER_VALIDATE_BOOLEAN); // true
filter_var( 'true', FILTER_VALIDATE_BOOLEAN); // true
filter_var( 1, FILTER_VALIDATE_BOOLEAN); // true
filter_var( '1', FILTER_VALIDATE_BOOLEAN); // true
filter_var( 'on', FILTER_VALIDATE_BOOLEAN); // true
filter_var( 'yes', FILTER_VALIDATE_BOOLEAN); // true
filter_var( false, FILTER_VALIDATE_BOOLEAN); // false
filter_var( 'false', FILTER_VALIDATE_BOOLEAN); // false
filter_var( 0, FILTER_VALIDATE_BOOLEAN); // false
filter_var( '0', FILTER_VALIDATE_BOOLEAN); // false
filter_var( 'off', FILTER_VALIDATE_BOOLEAN); // false
filter_var( 'no', FILTER_VALIDATE_BOOLEAN); // false
filter_var('asdfasdf', FILTER_VALIDATE_BOOLEAN); // false
filter_var( '', FILTER_VALIDATE_BOOLEAN); // false
filter_var( null, FILTER_VALIDATE_BOOLEAN); // false
/**
* 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.