(PECL ds >= 1.0.0)
Ds\Map::diff — Creates a new map using keys that aren't in another map
Returns the result of removing all keys from the current instance that are
present in a given map.
A \ B = {x ∈ A | x ? B}
mapThe map containing the keys to exclude in the resulting map.
The result of removing all keys from the current instance that are
present in a given map.
Example #1 Ds\Map::diff() example
<?php
$a = new \Ds\Map(["a" => 1, "b" => 2, "c" => 3]);
$b = new \Ds\Map(["b" => 4, "c" => 5, "d" => 6]);
var_dump($a->diff($b));
?>
以上例程的输出类似于：
object(Ds\Map)#3 (1) {
[0]=>
object(Ds\Pair)#4 (2) {
["key"]=>
string(1) "a"
["value"]=>
int(1)
}
}