Repeat vs Cond

I have a little question about =REPEAT vs COND=

Look at this LISP-monster:

(setq rlst '())
(setq lst1 '(1.0 2.0 3.0 4.0))
(setq lst2 '(0.0 -1.5 -3.0 4.5 6.0))
(setq lst3 lst2);| helper list|;
(repeat (length lst1)
(repeat (length lst2)
(setq rlst (append rlst
(reverse (list (cons (car lst2) (list (car lst1)))))
)
)
(setq lst2 (cdr lst2))
lst1
)
(setq lst2 lst3)
(setq lst1 (cdr lst1))
rlst
)
(print rlst)
; result list :
((0.0 1.0) (-1.5 1.0) (-3.0 1.0) (4.5 1.0) (6.0 1.0)
(0.0 2.0) (-1.5 2.0) (-3.0 2.0) (4.5 2.0) (6.0 2.0)
(0.0 3.0) (-1.5 3.0) (-3.0 3.0) (4.5 3.0) (6.0 3.0)
(0.0 4.0) (-1.5 4.0) (-3.0 4.0) (4.5 4.0) (6.0 4.0))

Why can I substitute this expression for COND function
like this:
(defun VLF-APPEND-X-COORD (X LENGTH-LIST)
(if (null LENGTH-LIST)
nil
(append (mapcar 'list (list X) LENGTH-LIST)
(VLF-APPEND-X-COORD X (cdr LENGTH-LIST)))))
;Example:
(setq X 3.0);|constant|;
(setq LENGTH-LIST '(101 104 105 106))
(VLF-APPEND-X-COORD X LENGTH-LIST)
; result : ((3.0 101) (3.0 104) (3.0 105) (3.0 106))

 

Hi Fatty

Monster substitute:

Code:

(defun MergeLists (Ls1 Ls2)
(apply 'append
(mapcar
'(lambda (l1)
(mapcar '(lambda (l2) (list l2 l1)) Ls2)
) Ls1
)
)
)
Call:
(MergeLists '(1.0 2.0 3.0 4.0) '(0.0 -1.5 -3.0 4.5 6.0))
Returns:
((0.0 1.0) (-1.5 1.0) (-3.0 1.0) (4.5 1.0) (6.0 1.0)
(0.0 2.0) (-1.5 2.0) (-3.0 2.0) (4.5 2.0) (6.0 2.0)
(0.0 3.0) (-1.5 3.0) (-3.0 3.0) (4.5 3.0) (6.0 3.0)
(0.0 4.0) (-1.5 4.0) (-3.0 4.0) (4.5 4.0) (6.0 4.0)
)

I don't know what you wanna do with 'cond', but to get the same
result like your sample use this:

Code:

(defun VLF-APPEND-X-COORD (Con Lst)
(if Lst (mapcar '(lambda (l) (list Con l)) Lst))
)

Cheers

 

Thanks for your help,
this is a lot nicer than my abrahcadabrah.
I hope my programm will be operate trouble-free.

Our routine need me to be construct a
ground profile and water pipeline.

Best regards,
Fatty

 

Glad to help you...¦-)

Cheers

 

Hi, Jurg!
I'm understand your suggestion...
Excuse me for my aplomb, next time I will
be naming my functions "quietly".
Thanks more.
Apropos, on your site are excellent routines,
to all intents and purposes efficiency.

Best whishes and good luck,
press Enter with care!
Fatty.

<>

 

Hi Fatty

Thanks for the flowers...¦-)

Cheers

 

Hi, Juergen!

You are welcome...¦-)
How to write U-umlaut in \M-code?

Fatty

 

Hi Fatty

press Alt-Key and write 129 on active Num block -> ü

Cheers