Min and Max of a list of Associations

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up vote
10
down vote

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I am trying to find the minimum values for all elements in a list of associations, below is an example



x = "a"->12, "b"->3, "c"->21



Required output for Min
<



Required output for Max
"a"-> 21, "b"->11, "c"->15




My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1



for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15



Is there an elegant way to achieve this result?






list-manipulation associations







share|improve this question



















  • 1




    I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
    – Shredderroy
    Dec 7 at 6:30














up vote
10
down vote

favorite
1












I am trying to find the minimum values for all elements in a list of associations, below is an example



x = "a"->12, "b"->3, "c"->21



Required output for Min
<



Required output for Max
"a"-> 21, "b"->11, "c"->15




My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1



for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15



Is there an elegant way to achieve this result?






list-manipulation associations







share|improve this question



















  • 1




    I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
    – Shredderroy
    Dec 7 at 6:30












up vote
10
down vote

favorite
1









up vote
10
down vote

favorite
1






1





I am trying to find the minimum values for all elements in a list of associations, below is an example



x = "a"->12, "b"->3, "c"->21



Required output for Min
<



Required output for Max
"a"-> 21, "b"->11, "c"->15




My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1



for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15



Is there an elegant way to achieve this result?






list-manipulation associations







share|improve this question















I am trying to find the minimum values for all elements in a list of associations, below is an example



x = "a"->12, "b"->3, "c"->21



Required output for Min
<



Required output for Max
"a"-> 21, "b"->11, "c"->15




My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1



for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15



Is there an elegant way to achieve this result?






list-manipulation associations




list-manipulation associations






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 7 at 6:22









C. E.

49.4k395200




49.4k395200










asked Dec 7 at 5:39









Professor Williams

533




533







  • 1




    I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
    – Shredderroy
    Dec 7 at 6:30












  • 1




    I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
    – Shredderroy
    Dec 7 at 6:30







1




1




I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
– Shredderroy
Dec 7 at 6:30




I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
– Shredderroy
Dec 7 at 6:30










3 Answers
3






active

oldest

votes

















up vote
13
down vote



accepted










How about



a = >,
 <;

Merge[a, Min]

(*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

Merge[a, Max]

(*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)


EDIT



Improved, as per Kuba's suggestion.






share|improve this answer





























    up vote
    6
    down vote













    Random`Private`MapThreadMin[x]
    Random`Private`MapThreadMax[x]



    <|"a" -> 4, "b" -> 3, "c" -> 1|>



    <|"a" -> 21, "b" -> 11, "c" -> 21|>







    share|improve this answer
















    • 1




      is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
      – Soner
      Dec 7 at 12:33






    • 1




      A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
      – Henrik Schumacher
      Dec 7 at 13:45










    • Thanks, I am checking the link right now :)
      – Soner
      Dec 7 at 21:35

















    up vote
    1
    down vote













    You may use Query and MinMax.



    With x as in OP.



    Query[Transpose /* Map[MinMax]]@x



    <|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>



    You can produce a more descriptive result with AssociationThread.



    res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x



    <|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
     "b" -> <|"Min" -> 3, "Max" -> 11|>, 
     "c" -> <|"Min" -> 1, "Max" -> 21|>|>



    Which you can then access by Key with Association's syntax sugar.



    res["a", "Max"]



    21



    Hope this helps.






    share|improve this answer




















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      3 Answers
      3






      active

      oldest

      votes








      3 Answers
      3






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes








      up vote
      13
      down vote



      accepted










      How about



      a = >,
       <;

      Merge[a, Min]

      (*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

      Merge[a, Max]

      (*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)


      EDIT



      Improved, as per Kuba's suggestion.






      share|improve this answer


























        up vote
        13
        down vote



        accepted










        How about



        a = >,
         <;

        Merge[a, Min]

        (*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

        Merge[a, Max]

        (*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)


        EDIT



        Improved, as per Kuba's suggestion.






        share|improve this answer
























          up vote
          13
          down vote



          accepted







          up vote
          13
          down vote



          accepted






          How about



          a = >,
           <;

          Merge[a, Min]

          (*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

          Merge[a, Max]

          (*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)


          EDIT



          Improved, as per Kuba's suggestion.






          share|improve this answer














          How about



          a = >,
           <;

          Merge[a, Min]

          (*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

          Merge[a, Max]

          (*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)


          EDIT



          Improved, as per Kuba's suggestion.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Dec 7 at 8:30

























          answered Dec 7 at 6:22









          Shredderroy

          1,4931115




          1,4931115




















              up vote
              6
              down vote













              Random`Private`MapThreadMin[x]
              Random`Private`MapThreadMax[x]



              <|"a" -> 4, "b" -> 3, "c" -> 1|>



              <|"a" -> 21, "b" -> 11, "c" -> 21|>







              share|improve this answer
















              • 1




                is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
                – Soner
                Dec 7 at 12:33






              • 1




                A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
                – Henrik Schumacher
                Dec 7 at 13:45










              • Thanks, I am checking the link right now :)
                – Soner
                Dec 7 at 21:35














              up vote
              6
              down vote













              Random`Private`MapThreadMin[x]
              Random`Private`MapThreadMax[x]



              <|"a" -> 4, "b" -> 3, "c" -> 1|>



              <|"a" -> 21, "b" -> 11, "c" -> 21|>







              share|improve this answer
















              • 1




                is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
                – Soner
                Dec 7 at 12:33






              • 1




                A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
                – Henrik Schumacher
                Dec 7 at 13:45










              • Thanks, I am checking the link right now :)
                – Soner
                Dec 7 at 21:35












              up vote
              6
              down vote










              up vote
              6
              down vote









              Random`Private`MapThreadMin[x]
              Random`Private`MapThreadMax[x]



              <|"a" -> 4, "b" -> 3, "c" -> 1|>



              <|"a" -> 21, "b" -> 11, "c" -> 21|>







              share|improve this answer












              Random`Private`MapThreadMin[x]
              Random`Private`MapThreadMax[x]



              <|"a" -> 4, "b" -> 3, "c" -> 1|>



              <|"a" -> 21, "b" -> 11, "c" -> 21|>








              share|improve this answer












              share|improve this answer



              share|improve this answer










              answered Dec 7 at 6:34









              Henrik Schumacher

              47.6k466134




              47.6k466134







              • 1




                is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
                – Soner
                Dec 7 at 12:33






              • 1




                A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
                – Henrik Schumacher
                Dec 7 at 13:45










              • Thanks, I am checking the link right now :)
                – Soner
                Dec 7 at 21:35












              • 1




                is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
                – Soner
                Dec 7 at 12:33






              • 1




                A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
                – Henrik Schumacher
                Dec 7 at 13:45










              • Thanks, I am checking the link right now :)
                – Soner
                Dec 7 at 21:35







              1




              1




              is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
              – Soner
              Dec 7 at 12:33




              is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
              – Soner
              Dec 7 at 12:33




              1




              1




              A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
              – Henrik Schumacher
              Dec 7 at 13:45




              A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
              – Henrik Schumacher
              Dec 7 at 13:45












              Thanks, I am checking the link right now :)
              – Soner
              Dec 7 at 21:35




              Thanks, I am checking the link right now :)
              – Soner
              Dec 7 at 21:35










              up vote
              1
              down vote













              You may use Query and MinMax.



              With x as in OP.



              Query[Transpose /* Map[MinMax]]@x



              <|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>



              You can produce a more descriptive result with AssociationThread.



              res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x



              <|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
               "b" -> <|"Min" -> 3, "Max" -> 11|>, 
               "c" -> <|"Min" -> 1, "Max" -> 21|>|>



              Which you can then access by Key with Association's syntax sugar.



              res["a", "Max"]



              21



              Hope this helps.






              share|improve this answer
























                up vote
                1
                down vote













                You may use Query and MinMax.



                With x as in OP.



                Query[Transpose /* Map[MinMax]]@x



                <|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>



                You can produce a more descriptive result with AssociationThread.



                res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x



                <|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
                 "b" -> <|"Min" -> 3, "Max" -> 11|>, 
                 "c" -> <|"Min" -> 1, "Max" -> 21|>|>



                Which you can then access by Key with Association's syntax sugar.



                res["a", "Max"]



                21



                Hope this helps.






                share|improve this answer






















                  up vote
                  1
                  down vote










                  up vote
                  1
                  down vote









                  You may use Query and MinMax.



                  With x as in OP.



                  Query[Transpose /* Map[MinMax]]@x



                  <|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>



                  You can produce a more descriptive result with AssociationThread.



                  res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x



                  <|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
                   "b" -> <|"Min" -> 3, "Max" -> 11|>, 
                   "c" -> <|"Min" -> 1, "Max" -> 21|>|>



                  Which you can then access by Key with Association's syntax sugar.



                  res["a", "Max"]



                  21



                  Hope this helps.






                  share|improve this answer












                  You may use Query and MinMax.



                  With x as in OP.



                  Query[Transpose /* Map[MinMax]]@x



                  <|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>



                  You can produce a more descriptive result with AssociationThread.



                  res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x



                  <|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
                   "b" -> <|"Min" -> 3, "Max" -> 11|>, 
                   "c" -> <|"Min" -> 1, "Max" -> 21|>|>



                  Which you can then access by Key with Association's syntax sugar.



                  res["a", "Max"]



                  21



                  Hope this helps.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Dec 7 at 10:30









                  Edmund

                  25.5k330100




                  25.5k330100



























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