{func} is called for every item in {object}, which can be a |String|, |List| or a |Blob|. {func} is called with two arguments: the result so far and current item. After processing all items the result is returned. {initial} is the initial result. When omitted, the first item in {object} is used and {func} is first called for the second item. If {initial} is not given and {object} is empty no result can be computed, an E998 error is given. Examples: echo reduce([1, 3, 5], { acc, val -> acc + val }) echo reduce(['x', 'y'], { acc, val -> acc .. val }, 'a') echo reduce(0z1122, { acc, val -> 2 * acc + val }) echo reduce('xyz', { acc, val -> acc .. ',' .. val }) Can also be used as a |method|: echo mylist->reduce({ acc, val -> acc + val }, 0)