How to specify optional string parameters in a function signature and identify the pattern

As a newbie, I've got a rather simple question.

I would like to define a function that accepts one of a few possible strings.

I.e., I wish to do the following.

f[s_"a"|"b"] := do something useful with s


But of course that syntax doesn't work. Note that the function definition is not overloaded.

I achieved this the following way.

f[key2_ /; MemberQ[Map[StringMatchQ[key2, #] &, "Cat", "Bird", "Mouse"], True]] := someAssoc["Key1"][key2]


Is there a better way to express this?

1 Answer
1

You can use Pattern:

Pattern

f[s : "a" | "b"] := s <> ": stuff"
f /@ "a", "b", "c", 2


"a: stuff", "b: stuff", f["c"], f[2]

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