I have
a["tree"] := "oak"
a["flower"] := "rose"
a["dog" | "cat"] := "animals"
I want that the last definition of a behaves differently like in
b[x_ /; x == "dog" || x == "cat"] := If[x == "dog", "wow", "miau"]
but want to do this with a
Is there a way to write something like
a["dog" | "cat"] := If[ (* passed parameter *) == "dog", "wow", "miau"]
The clearest and fastest (execution time) method is to simply use two definitions:
a["dog"] = "wow";
a["cat"] = "miau";
On reflection this is so straightforward that I doubt I understand your question or the reason behind it. Could you give another example, please?
A related question:
Alternatives. I agree that a Swift makes it long again, but would not say at this point that Kuba's comment is without advantages in some cases.
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Switch for both performance and clarity.
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Commented
Jun 6, 2014 at 11:14
alt = {"dog", "cat"}; val = {1, 2}; ClearAll[a]; MapThread[Set, {a /@ alt, val}];
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Piecewise, if this is a matter of visual formatting. (Assuming use of the Notebook interface.)
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Commented
Jun 6, 2014 at 11:18
g[2] = 28 ... ) because of its clarity. In a certain sense my question was a duplicate. You should add that link to your answer.
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a[x : "dog" | "cat"] := Switch[x, "dog", 1, "cat", 2]? P.s. there is not need for:=in first two cases. $\endgroup$Switchif possible; please read this: (2618) $\endgroup$