Elm Language Lists and Iteration Pattern Matching on a list
Example
We can match on lists like any other data type, though they are somewhat unique, in that the constructor for building up lists is the infix function ::. (See the example Creating a list for more on how that works.)
matchMyList : List SomeType -> SomeOtherType
matchMyList myList =
case myList of
[] ->
emptyCase
(theHead :: theRest) ->
doSomethingWith theHead theRest
We can match as many elements in the list as we want:
hasAtLeast2Elems : List a -> Bool
hasAtLeast2Elems myList =
case myList of
(e1 :: e2 :: rest) ->
True
_ ->
False
hasAtLeast3Elems : List a -> Bool
hasAtLeast3Elems myList =
case myList of
(e1 :: e2 :: e3 :: rest) ->
True
_ ->
False
