Re: Appending to a list

[Joost Kremers]

On Sun, Dec 13 2020, steve-humphreys@gmx.com wrote:
> Would appending to list like this be good?
>
> (setq bird '("Toucan" "King Fisher"))
> (setq bird (append bird ("Swift") ))

This should result in an error, because `("Swift")` isn't quoted. You'd need:

    (setq bird (append bird '("Swift")))

But note that the last argument of `append` isn't copied, so it may not be a
good idea to use a literal list.

> Or does one customarily use other constructs for
> adding to a list?

`push` is what I would use:

    (push "Swift" bird)

No need to use `setq` here.

`push` won't check if the element is already in the list, though. You can use
`cl-pushnew` in that case, but be sure to load the library it's in:

    (require 'cl-lib)
    (cl-pushnew "Swift" bird)

HTH

-- 
Joost Kremers
Life has its moments