Re: Advantage using mapc over dolist

[Tomas Hlavaty <tom@logand.com>]

On Mon 02 Dec 2024 at 17:03, Heime via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> wrote:
> Had thought the mapc would be faster.

mapc calls a function (length list) times, so unless the compiler is
clever enough to optimize this call away, it will be "slower"

however, if you want fast code, do not traverse lists whole and linearly
in the first place.  instead, try to place the loop as far outside as
possible

> With dolist I can exit with (return) or catch-throw, can one do the
> same with mapc?

yes

> For what cases is mapc useful?

for side-effects, if you have the body of the loop as a function
already