reduce

Reduces the list to a single value by applying the given function to each element, accumulating the result from the initial value.

Example:

    var list = new ArrayList<string> (GLib.str_equal);
    list.add ("a");
    list.add ("b");
    list.add ("c");
    var joined = list.reduce<string> ("", (acc, s) => {
        return acc + s;
    });
    assert (joined == "abc");

Parameters:

initial	the initial accumulator value.
func	the reduction function.

Returns:

the final accumulated value.