I had looked at previous answers for this but was unable to find a solution. I have the following code:




The positions of the strings given in "dnames1" correspond to the values in the same position given by list "dnumber" (this can be seen through the AssociationThread). I then rearranged the list "dnumber" to go from the smallest number to the largest, giving a new list designated "newdnumber." I'm trying to then produce a new corresponding list called "newdnames1" which reflects the new ordering given by "newdnumber." This would give an output of:


I've tried the following to solve this question:


but the main issue is that the AssociationThreaddoes not associate the correct list of strings if there are repeating values given in dnumber (I.e. The number 20 appears 3 times but the association only ever assigns "A6"`a value of 20 and it never assigns strings "A1" or "A2". Any help producing newdnames1 would be greatly appreciated.

  • 1
    $\begingroup$ why not just dnames1[[Ordering[dnumber]]] to get newdnames1 directly? $\endgroup$
    – kglr
    Commented Jun 10, 2020 at 22:59
  • 1
    $\begingroup$ If you insist on using associations, you could use Keys@Sort@AssociationThread[dnames1, dnumber] $\endgroup$
    – MarcoB
    Commented Jun 10, 2020 at 23:55

1 Answer 1


You can get newdnames1 directly using


If you you want to work with associations, for newdnumber, you can get the desired result simply using Sort:

assoc1 = AssociationThread[dnames1, dnumber]
<|"A1" -> 20, "A2" -> 20, "A3" -> 11, "A4" -> 21, "A5" -> 19,   "A6" -> 20|>
assoc2b = Sort[assoc1]
 <|"A3" -> 11, "A5" -> 19, "A1" -> 20, "A2" -> 20, "A6" -> 20,  "A4" -> 21|>
Keys @ assoc2
 {"A3", "A5", "A1", "A2", "A6", "A4"}

For general newdnumber, you can sort assoc1 using SortBy[PositionIndex[newdnumber]]:

assoc2 = SortBy[PositionIndex[newdnumber]]@assoc1
<|"A3" -> 11, "A5" -> 19, "A4" -> 21, "A1" -> 20, "A2" -> 20,  "A6" -> 20|>
Keys @ assoc2
 {"A3", "A5", "A1", "A2", "A6", "A4"}

shuffledDnumber = RandomSample[dnumber]
 {19, 11, 20, 20, 21, 20}
assoc3 = SortBy[PositionIndex[shuffledDnumber]]@assoc1
<|"A5" -> 19, "A3" -> 11, "A4" -> 21, "A1" -> 20, "A2" -> 20,  "A6" -> 20|>
Keys @ assoc3
{"A5", "A3", "A4", "A1", "A2", "A6"}

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