# [plt-scheme] creating nested lists in DrScheme

 From: Aniket Karmarkar (akarmarkar at mail.bradley.edu) Date: Fri May 7 22:42:50 EDT 2010 Previous message: [plt-scheme] creating nested lists in DrScheme Next message: [plt-scheme] creating nested lists in DrScheme Messages sorted by: [date] [thread] [subject] [author]

```This is what I am trying to do.
Write the function partialpaths, of two arguments. The first argument is a
list of lists, representing a graph(adjacency list representation of a
graph). The second argument is a partial path in the reverse order, for
example the path "from a to b to c" is represented by the list (c b a). The
function should return a list of sublists containing all possible expansions
of this partial path by one node. For example: (partialpaths '( (a b c) (b c
d) (c d a) (d)) '(b a)) should return: ( (c b a) (d b a))
I get the (b c d) part now I need to attach the cdr of this to b a multiple
times so I try putting it in a loop.

Here's what I have:
(define nod ())
(define ma '('()))
(define (partialpaths L1 L2)
(set! nod (equal L1 L2))
(do()
;exit test
((null? (cdr nod)))
(list ma (attach(cdr nod)L2))
(set! nod (cdr nod))
)
ma
)

(define (attach List1 List2)
(list (car List1) List2)
)

(define (equal L1 L2)
(cond
((eq? (caar L1) (car L2)) (car L1))
(else (equal (cdr L1) L2))
)
)

On Fri, May 7, 2010 at 9:29 PM, Jon Rafkind <rafkind at cs.utah.edu> wrote:

>  (list 1 (list 2))
>
>
> On 05/07/2010 08:29 PM, Aniket Karmarkar wrote:
>
> I am really stuck. I want to create a nested list.
> Thanks,
> Aniket
>
>
>
>
> _________________________________________________