22b. List Exercises 1.5

1. more-rand: number(x) list of numbers(nums) -> list of numbers Give a new list with x and an additional random number from 0 through 9 put on the front of the more-rand list.

    (check-random (more-rand 5 (list 1 2 3)) 
                  (list 5 (random 10) 1 2 3))
   

2. maybe-no-5: list of numbers -> list of numbers. If the first number in the list is a 5, skip it, otherwise return the whole list.

    (check-expect (maybe-no-5 (list 1 5 51)) (list 1 5 51))
    (check-expect (maybe-no-5 (list 5 9 14 23)) (list 9 14 23))
   

3. pemo: list of numbers -> number. Find the sum (plus) all of the even numbers in the list and subtract (minus) all of the odd numbers in the list.

    (check-expect (pemo (list 10 30 5 20 10 11)) 54)
   

4. cram-small: list of strings(words) -> string. Take all of the words that are less than 5 letters long and combine them all into one big string.

    (check-expect (cram-small (list "cat" "goose" "bear" "dolphin")) "catbear")