python help Q7: No Repeats Implement no-repeats, which takes a list of numbers s as input and returns a list that has all of the unique elements of s in the order that they first appear, but no repeats. For example, (no-repeats (list 5 4 5 4 2 2)) evaluates to (5 4 2). Hints: To test if two numbers are equal, use the = procedure. To test if two numbers are not equal, use the not procedure in combination with =. You may find it helpful to use the filter procedure. (define (no-repeats s) 'YOUR-CODE-HERE ) ;;; Tests (no-repeats (list 5 4 5 4 2 2)) ; expect (5 4 2)
python help
Q7: No Repeats
Implement no-repeats, which takes a list of numbers s as input and returns a list that has all of the unique elements of s in the order that they first appear, but no repeats. For example, (no-repeats (list 5 4 5 4 2 2)) evaluates to (5 4 2).
Hints: To test if two numbers are equal, use the = procedure. To test if two numbers are not equal, use the not procedure in combination with =. You may find it helpful to use the filter procedure.
|
(define (no-repeats s)
'YOUR-CODE-HERE
) ;;; Tests (no-repeats (list 5 4 5 4 2 2)) ; expect (5 4 2) |
Q8: Substitute
Write a procedure substitute that takes three arguments: a list s, an old word, and a new word. It returns a list with the elements of s, but with every occurrence of old replaced by new, even within sub-lists.
Hint: The built-in pair? predicate returns True if its argument is a cons pair.
Hint: The = operator will only let you compare numbers, but using equal? or eq? will let you compare symbols as well as numbers. For more information, check out the Scheme Built-in Procedure Reference.
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(define (substitute s old new)
'YOUR-CODE-HERE
) |
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