AutoLISP -- Extracting a string from a List of Lists?

Question

Working in AutoLISP. I am looking for a more elegant way to extract the second string in this list of lists...

(("FullName") ("Larry Paige"))

Currently using the following to extract desired data.

(setq _BAMOFO (nth 0 (nth 1 Result)))

Thank you.

coredump · Accepted Answer · 2025-02-25 09:46:18Z

1

The most readable approach to me would be to be able to write:

(setq _BAMOFO (fullname result))

And you need to define a fullname accessor function. Then you do not really care about how it is implemented; nth is quite readable in my opinion.

(defun fullname (list)
  (nth 0 (nth 1 list)))

Or maybe you can find a more robust way to extract the name given the shape of your data, for example finding out the list that follows the list that contains "FullName", that's not entirely clear to me if that makes sense in your context.

edited Feb 25 at 9:46

answered Feb 19 at 13:37

coredump

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Comments

GoCoder · Accepted Answer · 2025-08-12 00:20:29Z

1

if all the sublists always contain just one string each, then it is also a good way to unwrap the list(Result) first, if you use it several times after.

(setq Result '(("FullName") ("Larry Paige"))) ; => (("FullName") ("Larry Paige"))
(setq unwrapped_list (mapcar 'car Result)) ; => ("FullName" "Larry Paige")
(setq _BAMOFO (nth 1 unwrapped_list)) ; => "Larry Paige"

edited Aug 12 at 0:20

answered Aug 4 at 4:10

GoCoder

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Amadan · Accepted Answer · 2025-02-19 00:27:50Z

0

Fully low-level way:

(car (car (cdr Result)))

Mixed way that is likely more readable, as it is closer to human intuition of what we want to get:

(car (nth 1 Result))

answered Feb 19 at 0:27

Amadan

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3 Comments

Shawn Feb 19 at 21:03

Does autolisp have the classic car/cdr combinations like caadr?

Shawn Feb 19 at 21:07

Answering my own question, I only saw cadr and caddr in the documentation. So (car (cadr Result)) could be another variation.

Will Ness Aug 4 at 16:40

@Shawn yes it does, the usual combos up to four letters long. cadr would be even more idiomatic than nth 1, I think.

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