``reduce`` ========== The ``reduce`` filter iteratively reduces a sequence or a mapping to a single value using an arrow function, so as to reduce it to a single value. The arrow function receives the return value of the previous iteration and the current value of the sequence or mapping: .. code-block:: twig {% set numbers = [1, 2, 3] %} {{ numbers|reduce((carry, v) => carry + v) }} {# output 6 #} The ``reduce`` filter takes an ``initial`` value as a second argument: .. code-block:: twig {{ numbers|reduce((carry, v) => carry + v, 10) }} {# output 16 #} Note that the arrow function has access to the current context. Arguments --------- * ``arrow``: The arrow function * ``initial``: The initial value