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Some weeks ago, I posted a question which involved creating string pairs from a list of string elements. One of the answers posted (by Kuba) worked very well until I found an example where it didn't. Here it is:

lis = {"ABCDEFGHI" | "JKLMN OP" | "PQR" | "JKLMN" | "OPXYZ"};
prs = {"JKLMN OP ABCDEFGHI", "JKLMN OPXYZ", "PQR JKLMN"};

Given the list prs whose elements consist of two members of lis separated by a space, the task is to create a modified prs where the elements of prs are separated into two elements that are members of lis.

Kuba's suggestion was essentially:

separatedNames = Table[StringSplit[prs[[i]]], {i, Length[prs]}];
alternative = Apply[Alternatives]@Reverse@SortBy[StringLength]@lis[[1]];
res = Partition[Flatten[StringCases[alternative] /@ StringRiffle /@ separatedNames],2]

This produces: {{"JKLMN OP", "ABCDEFGHI"}, {"JKLMN OP", "PQR"}}

and not the desired: {{"JKLMN OP","ABCDEFGHI"},{"JKLMN","OPXYZ"},{"PQR","JKLMN"}}

As always thanks for thoughts.

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1 Answer 1

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as = Association[StringRiffle@#->#&/@(Join[#, Reverse/@#]&@Subsets[List @@ lis[[1]], {2}])]

as[[prs]]

<|"JKLMN OP ABCDEFGHI" -> {"JKLMN OP", "ABCDEFGHI"}, "JKLMN OPXYZ" -> {"JKLMN", "OPXYZ"}, "PQR JKLMN" -> {"PQR", "JKLMN"}|>

as /@ prs

{{"JKLMN OP", "ABCDEFGHI"}, {"JKLMN", "OPXYZ"}, {"PQR", "JKLMN"}}

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  • $\begingroup$ Thank you, kglr, that works well. $\endgroup$
    – Suite401
    Commented Nov 13, 2018 at 16:11
  • $\begingroup$ a question: It would be desirable to preserve the order of the pairs in the output of assoc/@prs to be the same as in prs (i.e., the first element would be {"JKLMN OP","ABCDEFGHI"} and not {"ABCDEFGHI","JKLMN OP"}. Thanks $\endgroup$
    – Suite401
    Commented Nov 25, 2018 at 21:39
  • $\begingroup$ @Suite401, good point. I will update if i can find a solution. $\endgroup$
    – kglr
    Commented Nov 25, 2018 at 23:38
  • $\begingroup$ That would be very helpful, thank you. $\endgroup$
    – Suite401
    Commented Dec 9, 2018 at 8:17
  • $\begingroup$ @Suite401, updated. $\endgroup$
    – kglr
    Commented Dec 9, 2018 at 9:04

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