why serialize() fucntion is used in php code example

Example 1: php serialize array

$array["a"] = "Foo";
$array["b"] = "Bar";
$array["c"] = "Baz";
$array["d"] = "Wom";

$str = serialize($array);

Example 2: php array serialize

//If you plan to serialize and store it in file or database use below syntax
//to safely serialize
$safe_string_to_store = base64_encode(serialize($multidimensional_array));

//to unserialize...
$array_restored_from_db = unserialize(base64_decode($encoded_serialized_string));