Specs

all?(t()) :: boolean()

Returns true if all elements in enumerable are truthy.

When an element has a falsy value (false or nil) iteration stops immediately and false is returned. In all other cases true is returned.

Examples

iex> Enum.all?([1, 2, 3])
true

iex> Enum.all?([1, nil, 3])
false

iex> Enum.all?([])
true

Specs

all?(t(), (element() -> as_boolean(term()))) :: boolean()

Returns true if fun.(element) is truthy for all elements in enumerable.

Iterates over enumerable and invokes fun on each element. If fun ever returns a falsy value (false or nil), iteration stops immediately and false is returned. Otherwise, true is returned.

Examples

iex> Enum.all?([2, 4, 6], fn x -> rem(x, 2) == 0 end)
true

iex> Enum.all?([2, 3, 4], fn x -> rem(x, 2) == 0 end)
false

iex> Enum.all?([], fn _ -> nil end)
true

As the last example shows, Enum.all?/2 returns true if enumerable is empty, regardless of fun. In an empty enumerable there is no element for which fun returns a falsy value, so the result must be true. This is a well-defined logical argument for empty collections.