racket

Example: How to convert list: '(0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15) Into list of lists: '((0 1 2 3) (4 5 6 7) (8 9 10 11) (12 13 14 15)) Based on answers provided here so far, this is what I've come up with: First define function to take up to 'n' elements from beginning of the list: (define (take-up-to n xs) (define (iter xs n taken) (cond [(or (zero? n) (empty? xs)) (reverse taken)] [else (iter (cdr xs) (- n 1) (cons (car xs) taken))])) (iter xs n '())) Second is similar function for the rest of list: (define (drop-up-to n xs) (define (iter xs n taken) (cond [(or (zero? n) (empty? xs)) xs

I understand that functions in Scheme/Racket like map, foldr, and filter, can do wonderful things like apply a function to a list of elements. Is it possible to apply a list of functions to a single element? I would like to generate the values produced by each of the functions, then find their maximum. Thank you. For the first part, this procedure will apply a list of functions to a single argument, assuming that all the functions receive only one argument. A list with the results is returned (define (apply-function-list flist element) (map (lambda (f) (f element)) flist)) For the second part,

Does Scheme or do any dialects of scheme have a kind of "self" operator so that anonymous lambdas can recur on themselves without doing something like a Y-combinator or being named in a letrec etc. Something like: (lambda (n) (cond ((= n 0) 1) (else (* n (self (- n 1))))))) No. The trouble with the "current lambda" approach is that Scheme has many hidden lambdas. For example: All the let forms (including let* , letrec , and named let ) do (which expands to a named let ) delay , lazy , receive , etc. To require the programmer to know what the innermost lambda is would break encapsulation, in

I'm just playing around with scheme/lisp and was thinking about how I would right my own definition of average . I'm not sure how to do some things that I think are required though. define a procedure that takes an arbitrary number of arguments count those arguments pass the argument list to (+) to sum them together Does someone have an example of defining average ? I don't seem to know enough about LISP to form a web search that gets back the results I'm looking for. The definition would be a very simple one-liner, but without spoiling it, you should look into: a "rest" argument -- this