[Maxima] "guarded" fetch from hashed array
vext01 at gmail.com
Tue Feb 7 12:29:32 CST 2012
On Tue, Feb 07, 2012 at 05:52:49PM +0000, Jaime Villate wrote:
> On 02/07/2012 04:38 PM, Edd Barrett wrote:
> >I wish to use a hash table to store a mapping from a variable name to a
> >list of coefficients. This is accomplished easily enough in maxima,
> >however, is there a way of throwing an error if the key accessed is not
> >a key in the hash table?
> Have you tried with atom?
> (%i2) hash[a]: "aaa"$
> (%i3) atom(hash[a]);
> (%o3) true
> (%i4) atom(hash[b]);
> (%o4) false
Actually, my hash contains lists, so I can use listp() similarly.
I bet there is a better way still...
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