a better way - apply/mapcar/lambda/mapcar/lambda

school me please.
I want to prefix '("BBB" "CCC" "DDD") with '("aaa" "AAA"), and combine as
one string, comma delimited.

(apply 'strcat
(apply 'append
(mapcar '(lambda (A )
(mapcar '(lambda (X )
(strcat A X ",")
)
'("BBB" "CCC" "DDD")
)
)
'("aaa" "AAA")
)))

correctly returns "aaaBBB,aaaCCC,aaaDDD,AAABBB,AAACCC,AAADDD,"

Is there a more elegant way of doing this?

 

(defun C:TEST ()
(setq str "")
(foreach a '("aaa" "bbb")
(foreach b '("BBB" "CCC" "DDD")
(setq str (strcat str a b ","))
)
)
)

 

Don't know if it's any better.......

(setq newlist '())
(foreach x '("aaa" "AAA")
(setq newlist
(append newlist
(mapcar
'(lambda (y)
(strcat x y ","))
'("BBB" "CCC" "DDD"))))
)

--
Ken Alexander
Acad2000
Windows2000 Prof.

"We can't solve problems by using the same kind
of thinking we used when we created them."
--Albert Einstein

 

Why are you trying to process without the foreach?

Devin

 

mapcar processes lists faster than foreach

 

I didn't know that, thanks!

Devin

 

Daron,

You might want to do a timing check, just to see which is faster in this
case. The other way seems to add steps in the process, which my increase
the runtime required.

Devin

 

There has been much of that here in the past. That's why i posted, hoping
one of the list pro's would chime in. Mine is overkill for the example, but
it's been simplified here for testing. When the '("BBB" "CCC" "DDD") list
contains over 100 items, it makes a difference.

 

I see.

Devin

 

Very minor change to your original:

(apply 'strcat
(mapcar '(lambda (y)
(apply 'strcat
(mapcar '(lambda (x)
(strcat y x ","))
'("BBB" "CCC" "DDD"))
))
'("aaa" "AAA")
)
)

--
Ken Alexander
Acad2000
Windows2000 Prof.

"We can't solve problems by using the same kind
of thinking we used when we created them."
--Albert Einstein

 

I believe that depends on the list.

 

As I seem to be learning. I found that when I switched to mapcar my list
processing was much faster. I wonder why it's foreach is slower?

Devin