How to convert list to string in Emacs Lisp

Question

How can I convert a list to string so I can call insert or message with it? I need to display c-offsets-alist but I got Wrong type argument: char-or-string-p for insert or Wrong type argument: stringp for message.

Georganngeorge

Answer 1

I am not sure of what you are trying to achieve, but format converts "stuff" to strings. For instance:

(format "%s" your-list)

will return a representation of your list. message uses format internally, so

(message "%s" your-list)

will print it

Amphiaster

Probably better %S instead of %s, to print the list in Lisp syntax. – Rentsch

Answer 2

(format) will embed parentheses in the string, e.g.:

ELISP> (format "%s" '("foo" "bar"))
"(foo bar)"

Thus if you need an analogue to Ruby/JavaScript-like join(), there is (mapconcat):

ELISP> (mapconcat 'identity '("foo" "bar") " ")
"foo bar"

Selector

Answer 3

Or

(prin1-to-string your-string)

Finally something special

(princ your-string)

Impermanent

Answer 4

M-x pp-eval-expression RET c-offsets-alist RET

Jp

Answer 5

If you need to convert a list like ((a b c d e)) to a string "a b c d e" then this function might help:

(defun convert-list-to-string (list)
  "Convert LIST to string."
  (let* ((string-with-parenthesis (format "%S" list))
     (end (- (length string-with-parenthesis) 2)))
    (substring string-with-parenthesis 2 end)))

Pitchman

I don't want to get rid of parentheses I want to display a list or a tree as it is. If you have a list of strings and want to convert that to sting you have other options than substring. You can create a function to convert any type of string and use (string-join (map 'symbol-name '(foo bar baz)) " ") here I use symbol-name but it should be any->string. – Georganngeorge

And your code will make no sense if you call it like this (convert-list-to-string '(foo bar (baz (quux)))) I think that you should ask another question because this is not the answer to my question. – Georganngeorge

This is just my solution, taking the answer of Alexander Gromnitsky and getting rid of parenthesis. I stumbled upon the problem of converting a list like ((a b c d e)) to a string "a b c d e". This works for me and I hope will help someone else. – Pitchman

This looks like an answer to a different question, how to convert ((a b c d e)) to a string "a b c d e" – Georganngeorge

@Georganngeorge The question is "How to convert list to string in Emacs Lisp?" And I found your question trying to get an answer to mine. Alexander Gromnitsky answered my question and I adapted it. And if I found your question smb may also just need my answer for their same question "How to convert list to string in Emacs Lisp?" – Pitchman