Topic: Question of the day #2

[Mark]

Given the following list show two ways of extracting the third ("three") item.

Code: [Select]

(setq lst '("one" "two" "three" "four" "five"))

[whdjr]

Here's my two ways.

Code: [Select]

(setq lst '("one" "two" "three" "four" "five"))
(setq 1way (caddr lst))
(setq 2way (nth 2 lst))

[Keith™]

Will, it looks like you got the 2 most common and concise methods.

[whdjr]

Yeppeee!!!
What prize do I win?

[SPDCad]

Is “the question of the day” for newbies?

I would feel funny answering most of these, or even worse I could answer them in such a complex way I might throw off, newbie!

As you mentioned above the two most common ways are shown, but I know of a few other methods, which get complex and basically a waste of time to programme. After all I try to write code is the simplest way possible with the fewest lines of code.

[SMadsen]

SPDCad, I think you should feel absolutely free to post your solutions, complex as well as simple.

[Mark]

All I can say is, if it looks like it's for newbies then it probably is.

But if you want to show your stuff, be my quest. I'm sure we can all learn something.

[Mark]

And here is how to return the others.

Code: [Select]


Command: (car lst) "one"
Command: (cadr lst) "two"
Command: (caddr lst) "three"
Command: (cadddr lst) "four"
Command: (last lst) "five"


(setq cntr 0)

  (while (< cntr (1- (length lst)))
         (princ
           (strcat
             "\n"(nth cntr lst)
             )
           )
         (setq cntr (1+ cntr))
         )


[David Bethel]

Code: [Select]

(caddr lst)

can also be parsed as:

Code: [Select]

(car (cdr (cdr lst)))

-David

[Keith™]

How about a redundant method.

Code: [Select]


(car (member (nth 2 lst) lst))


[CAB]

And here is how to return the others.

Here are some more.

Code: [Select]

(setq cntr 0)
(repeat (length lst)
  (princ (strcat "\n"(nth cntr lst)))
   (setq cntr (1+ cntr))
)

(foreach x lst
  (princ (strcat "\n" x))
)


(while lst
  (princ (strcat "\n" (car lst)))
  (setq lst (cdr lst))
)

[Fuccaro]

Code: [Select]

(setq lst '("one" "two" "three" "four" "five"))
(setq way1 (nth 2 lst)
      way2 (nth 2 (reverse lst))
      )
 
Or even better:

Code: [Select]

(setq ways (mapcar '(lambda(x) (nth 2 x)) (list lst (reverse lst))))