Re: [Maxima-discuss] How do I get the keys of a hash table in Maxima?

[Stavros M. <mac...@gm...>]

*arrayinfo*

But that's pretty ugly. We should really have an easy way of iterating over
a hasharray.


On Fri, Nov 14, 2025, 02:22 Eduardo Ochs <edu...@gm...> wrote:

> Hi list,
>
> how do I get the keys of a hash table in Maxima?
> Or, more concretely, if we run this,
>
>   myhash : make_array(hashed);
>   myhash[42] : 420;
>   myhash[ab] : "abab";
>   myhash[42];           /* 420 */
>   myhash[ab];           /* "abab" */
>   myhash[cd];           /* false */
>   to_lisp();
>     (loop for k being the hash-keys in #$myhash$
>           collect k)
>     (loop for k being the hash-keys in #$myhash$
>           if (not (eq k 'dim1))
>           collect k)
>     (to-maxima)
>
> The first LOOP returns (DIM1 42 $AB) and the second one
> returns (42 $AB)... but is there a standard way to get
> something like the result of the second loop without using
> Lisp?
>
> Some links:
>
> (info "(maxima)make_array")
>
> https://maxima.sourceforge.io/docs/manual/Data-Types-and-Structures.html#index-make_005farray
> https://sourceforge.net/p/maxima/code/ci/master/tree/src/ar.lisp
>
> Thanks in advance!
>   Eduardo Ochs
>   https://anggtwu.net/eev-maxima.html
>
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