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

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2
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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?




pattern-matching string-manipulation




share|improve this question
























    up vote
    2
    down vote

    favorite












    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?




    pattern-matching string-manipulation




    share|improve this question






















      up vote
      2
      down vote

      favorite









      up vote
      2
      down vote

      favorite











      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?




      pattern-matching string-manipulation




      share|improve this question












      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?





      pattern-matching string-manipulation





      share|improve this question











      share|improve this question




      share|improve this question










      asked Aug 25 at 21:43









      CalvinDale

      1694




      1694




















          1 Answer
          1






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          up vote
          3
          down vote



          accepted










          You can use Pattern:



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



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







          share|improve this answer




















          • Great thanks. As I suspected, the language has an affordance.
            – CalvinDale
            Aug 25 at 22:13










          • @CalvinDale, my pleasure. Thank you for the accept.
            – kglr
            Aug 25 at 22:15










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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          3
          down vote



          accepted










          You can use Pattern:



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



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







          share|improve this answer




















          • Great thanks. As I suspected, the language has an affordance.
            – CalvinDale
            Aug 25 at 22:13










          • @CalvinDale, my pleasure. Thank you for the accept.
            – kglr
            Aug 25 at 22:15














          up vote
          3
          down vote



          accepted










          You can use Pattern:



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



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







          share|improve this answer




















          • Great thanks. As I suspected, the language has an affordance.
            – CalvinDale
            Aug 25 at 22:13










          • @CalvinDale, my pleasure. Thank you for the accept.
            – kglr
            Aug 25 at 22:15












          up vote
          3
          down vote



          accepted







          up vote
          3
          down vote



          accepted






          You can use Pattern:



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



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







          share|improve this answer












          You can use Pattern:



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



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








          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Aug 25 at 21:50









          kglr

          158k8183382




          158k8183382











          • Great thanks. As I suspected, the language has an affordance.
            – CalvinDale
            Aug 25 at 22:13










          • @CalvinDale, my pleasure. Thank you for the accept.
            – kglr
            Aug 25 at 22:15
















          • Great thanks. As I suspected, the language has an affordance.
            – CalvinDale
            Aug 25 at 22:13










          • @CalvinDale, my pleasure. Thank you for the accept.
            – kglr
            Aug 25 at 22:15















          Great thanks. As I suspected, the language has an affordance.
          – CalvinDale
          Aug 25 at 22:13




          Great thanks. As I suspected, the language has an affordance.
          – CalvinDale
          Aug 25 at 22:13












          @CalvinDale, my pleasure. Thank you for the accept.
          – kglr
          Aug 25 at 22:15




          @CalvinDale, my pleasure. Thank you for the accept.
          – kglr
          Aug 25 at 22:15

















           

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