Question

Using Racket function "foldr" to produce a list of two-element lists consisting of one element from the first list and one element from the second list. For example '(1 2) and '(a b) -> '((1a) (1 b) (2 a) (2 b))

Answer 1

You can use the foldr function in Racket to produce a list of two-element lists from two input lists. You can use a lambda function with foldr to combine the elements of the two lists.

Step-by-step explanation:

In Racket, the foldr function is used to apply a binary operator between the elements of a list. To produce a list of two-element lists from two input lists, you can use foldr with a lambda function that takes each element from the first list and combines it with each element from the second list. Here's an example:

(define list1 '(1 2))

(define list2 '(a b))

(define result
(foldr (lambda (x acc)
(append (map (lambda (y)
(list x y))
list2)
acc))
'()
list1))

The

map

function is used to create a list of pairs by combining each element from list1 with every element from list2. The

append

function is then used to combine the resulting pairs with the accumulated list.