AFP Midtvejsevaluering

Result of:

[-2;3;5] |> List.map (fun x -> x*2)

• val it : int list = [-4; 6; 10]

• val it : float list = [-4.0; 6.0; 10.0]

• error FS0001: The type 'float' does not match the type 'int'

• val it: int list = []

Answer explanation

Map transforms input type to output type of same shape

F# is

• General purpose language with roots in FP

• Functional first language with strong types, support imperative, FP and OOP

• Purely functional with strong types

• General purpose language with support of OOP and FP

Answer explanation

F# is functional first language in the ML language family. But offers OOP programming and can even be used to web, devops and much more

Which is the higher order function(s) in F#

• 'a -> int -> 'b -> float option list

• 'a -> 'b -> ('c -> int)

• ('a -> int) -> 'c

• ('a -> int) -> ('b -> 'c) -> ('d -> float)

Answer explanation

Functions that return a function or take other functions as paremeter

F# is lazy evaluated

• True

• False

• Some

• None

Answer explanation

F# is eagerly evaluated - Haskell is lazyly.

Which is the polymorphic function(s) in F#

• (int -> float) -> int option -> float option

• int -> int list

• ('a -> 'b) -> 'a -> 'b

• int -> 'a list

Answer explanation

Polymorphic is also present in FP - sinze its just a way to state multiple forms.

Type of:

[1;2;3;4] |> List.fold (fun a b -> a + string b) ""

• val it : string list

• val it : string

• val it : int

• val it : int list

Result of:

[1;2;3;4] |> List.fold (fun a b -> string (int a + b)) "0"

• "0"

• "10"

• "11"

• "1234"

Answer explanation

Type name is a function that converts to that type eg 'int' and 'string'

Worst-case runtime of sets N and M:

Set.isSubset (set [1;2;3]) (set [2;3])

• O(M*log(N))

• O(N*M)

• O(N+M)

• O(N)

Answer explanation

We need to make M lookup in a Set of size N. Lookup in a tree

Result of:

Some "a" |> Option.fold (fun a b -> "b" + b + a) ""

• "ba"

• "b"

• "bba"

• "a"

Ouput of:

Seq.item 5 (Seq.cache (Seq.initInfinite (fun i -> printf "%i" i)))

• "1\n2\n3\n4\n5"

• "123456"

• "1234"

• "12345"

Answer explanation

It is 5 long and has no '\n' present :D