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Make partitions of lists in Scheme.

Make partitions of lists in Scheme.

(OP)
The objective is to split a list into two parts.

(define (partition number list)

Scheme will take a number and check the list. The numbers in the list that are less or equal to "number" shall be placed in one piece while the remaining parts are placed in another one.

ex. (partition 5 "(1 2 4 5 6 7 8 9)
> ((1 2 3 4 5) 6 7 8 9)

Im a bit unsure of how to fix this. Give an old man a helping hand.
Excuse my english.

RE: Make partitions of lists in Scheme.

(OP)
The allowed primitives are

car
cdr
cons
eq?
list?
list
load
null?
pair?
symbol?

Thanks.

RE: Make partitions of lists in Scheme.

What have you written ?

RE: Make partitions of lists in Scheme.

(OP)
Sorry, I dont have any.. yet. I specified my question quite bad i see now. What I really need is just a finger pointed in the right direction. I dont know where to start. In previous problems I've made for example a function:

"Write a procedure "subst-all", which takes an arbitrary list, which may contain dotted pairs, and
replaces all occurences of an element to another element".

It looks like this.

(define (subst-all val new-val list)
  (cond ((null? list) '())
        ((atom? list)
         (if (eq? val list)
             new-val
             list))
        ((atom? (car list))
         (if (eq? (car list) val)
             (cons new-val (subst-all val new-val (cdr list)))
             (cons (car list) (subst-all val new-val (cdr list)))))
        (else (cons (subst-all val new-val (car list))
                    (subst-all val new-val (cdr list))))))

I know this doesnt really help me much but it kinda shows wich level Im working on.

RE: Make partitions of lists in Scheme.

(OP)
Problem solved...

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