LISP programming help needed

[adlep]

Help...
This lisp programming is something very diffrient from what I have seen before...
Anyhow
Is it possible to modify this code so it is going to remove 3rd element from the list instead of the second?
The code:

(define deletesecond (lambda (L)
(cond
; if L isn't a list return null
((not (list? L)) '())

; if L has length less than 2 return null
((> 2 (length L)) '())

; return the cons of the head of L
; with the tail of the tail of L
(else (cons (car L)
(cdr (cdr L))
)
)
)
))

Help...
Thanks

 

[Kyteland]

I haven't had Lisp in a long time so this probably won't work. My editing is in bold.


--------------------------------------------------------------------------------

(define deletethird (lambda (L)
(cond
; if L isn't a list return null
((not (list? L)) '())

; if L has length less than 3 return null
((> 3 (length L)) '())

; return the cons of the head of L
; with the tail of the tail of L
(else (cons (car L)
(cdr (cdr (cdr L)))
)
)
)
))


--------------------------------------------------------------------------------


PS. Do your own homework from now on 😉

 

[xirtam]

Looks right to me Kyteland.

car returns the first, cdr returns all but the first, cons constructs.

 

[tkdkid]

To program effectively in lisp, drink a lot of alcohol and remember to stop every 10 minutes to bang your head against the wall...

 

[Beau]

thorry I can't be of more thervice. I theriouthly hope you get more help with your problemth.

 

[xirtam]

Long live the Language of Irritating Thingle Parenthetheth!

BTW: Does anybody else find it immoral that an "s" is included in the word "lisp"?

 

[Jzero]

Wow...
Lots of Insignificant, Silly Parenthesis!

 

[adlep]

Thanks folks, but I have figured it out..
Wrote a diffrient code...
And LISP IS RETARDED

(define (remove lis)
(cond
((null? lis) '())
((null? (cdr lis)) '())
((null? (cdr (cdr lis))) '())
(else (append (list (car lis) (car (cdr lis))) (cdddr lis)))
))

That works just fine!

 

[adlep]

Kyteland, thanks for the feedback, but your modification removes second and third element from the list:

(cdr (cdr (cdr L)))

I am doing my homework for myself....😀