Re: List of patterns for which a function is defined?
- To: mathgroup at smc.vnet.net
- Subject: [mg24409] Re: List of patterns for which a function is defined?
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Tue, 18 Jul 2000 00:58:08 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <8kjdh1$du2@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
ListOfPatternsDefined[a_Symbol] :=
First /@ DownValues[a] /. a[arg_] :> arg /.
Verbatim[HoldPattern][val_] :> val
will do it
Regards
Jens
Roger Wilson wrote:
>
> I have a function b which I define explicitly for a set of input values.
>
> a[1]=4; a[2]=5; a["cat"]="sam";
>
> If I type ??a I get the usual listing of the definition of a but how do I
> get a list of the values or patterns for which a is defined?
>
> ListOfPatternsDefined[a]
> {1,2,"cat"}
>
> In python this would be a.keys() but in Mathematica I'm stuck?
>
> Any ideas?
>