list

Measuring, searching and slicing lists. All the functions return new values; none changes a list.

list.size

list.size items -> Numb

Returns the number of items in the list items.

list.size [10, 20, 30]         # => 3
list.size []                   # => 0

list.enum

list.enum items -> Tuple

Returns the items of the list items as a tuple. An empty list gives Nothing, and a list of one item gives that item. Use it to map a function over the items of a list.

list.enum [10, 20, 30]         # => (10, 20, 30)
list.enum [5]                  # => 5
list.enum []                   # => ()
[list.enum [1, 2, 3] => (x -> x * 2)]    # => [2, 4, 6]

list.reverse

list.reverse items -> List

Returns a list with the items of the list items in reverse order.

list.reverse [1, 2, 3]         # => [3, 2, 1]

list.find

list.find item items -> Numb

Returns the position of the first item of the list items that is equal to item, or -1 if there is none. Positions start at 0.

list.find 20 [10, 20, 30, 20]  # => 1
list.find 99 [10, 20, 30]      # => -1
list.find [1] [[1], [2]]       # => 0

list.rfind

list.rfind item items -> Numb

Returns the position of the last item of the list items that is equal to item, or -1 if there is none.

list.rfind 20 [10, 20, 30, 20] # => 3

list.head

list.head n items -> List

Returns the first n items of the list items. A negative n returns all the items except the last -n. A fractional n is truncated toward zero.

list.head 2 [1, 2, 3, 4]       # => [1, 2]
list.head (-1) [1, 2, 3, 4]    # => [1, 2, 3]
list.head 10 [1, 2]            # => [1, 2]

list.tail

list.tail n items -> List

Returns the items of the list items from position n on, that is, all but the first n. A negative n returns the last -n items. A fractional n is truncated toward zero.

list.tail 1 [1, 2, 3, 4]       # => [2, 3, 4]
list.tail (-2) [1, 2, 3, 4]    # => [3, 4]