Iterate over keys of association












3














How do you iterate over the keys or rules of an association (in any order)? E.g. for 



<|"0"->"a", "1"->"b", "2"->"c"|>


I would like to either iterate over "0", "1", "2" or tuples containing each key and value.



For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).






associations







share|improve this question




















  • 1




    Simply use Map, KeyValueMap or KeyMap?
    – Henrik Schumacher
    Dec 5 at 19:20












  • Can you tell what exactly do you want to do?
    – Kuba♦
    Dec 5 at 21:42










  • Woooops! Done! :)
    – SLesslyTall
    Dec 6 at 7:40










  • @SLesslyTall You see, you want KeyValueMap[List] @ asso but who could've known :)
    – Kuba♦
    Dec 6 at 7:53
















3














How do you iterate over the keys or rules of an association (in any order)? E.g. for 



<|"0"->"a", "1"->"b", "2"->"c"|>


I would like to either iterate over "0", "1", "2" or tuples containing each key and value.



For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).






associations







share|improve this question




















  • 1




    Simply use Map, KeyValueMap or KeyMap?
    – Henrik Schumacher
    Dec 5 at 19:20












  • Can you tell what exactly do you want to do?
    – Kuba♦
    Dec 5 at 21:42










  • Woooops! Done! :)
    – SLesslyTall
    Dec 6 at 7:40










  • @SLesslyTall You see, you want KeyValueMap[List] @ asso but who could've known :)
    – Kuba♦
    Dec 6 at 7:53














3












3








3







How do you iterate over the keys or rules of an association (in any order)? E.g. for 



<|"0"->"a", "1"->"b", "2"->"c"|>


I would like to either iterate over "0", "1", "2" or tuples containing each key and value.



For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).






associations







share|improve this question















How do you iterate over the keys or rules of an association (in any order)? E.g. for 



<|"0"->"a", "1"->"b", "2"->"c"|>


I would like to either iterate over "0", "1", "2" or tuples containing each key and value.



For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).






associations




associations






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 6 at 7:40

























asked Dec 5 at 19:15









SLesslyTall

22317




22317








  • 1




    Simply use Map, KeyValueMap or KeyMap?
    – Henrik Schumacher
    Dec 5 at 19:20












  • Can you tell what exactly do you want to do?
    – Kuba♦
    Dec 5 at 21:42










  • Woooops! Done! :)
    – SLesslyTall
    Dec 6 at 7:40










  • @SLesslyTall You see, you want KeyValueMap[List] @ asso but who could've known :)
    – Kuba♦
    Dec 6 at 7:53














  • 1




    Simply use Map, KeyValueMap or KeyMap?
    – Henrik Schumacher
    Dec 5 at 19:20












  • Can you tell what exactly do you want to do?
    – Kuba♦
    Dec 5 at 21:42










  • Woooops! Done! :)
    – SLesslyTall
    Dec 6 at 7:40










  • @SLesslyTall You see, you want KeyValueMap[List] @ asso but who could've known :)
    – Kuba♦
    Dec 6 at 7:53








1




1




Simply use Map, KeyValueMap or KeyMap?
– Henrik Schumacher
Dec 5 at 19:20






Simply use Map, KeyValueMap or KeyMap?
– Henrik Schumacher
Dec 5 at 19:20














Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42




Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42












Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40




Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40












@SLesslyTall You see, you want KeyValueMap[List] @ asso but who could've known :)
– Kuba♦
Dec 6 at 7:53




@SLesslyTall You see, you want KeyValueMap[List] @ asso but who could've known :)
– Kuba♦
Dec 6 at 7:53










2 Answers
2






active

oldest

votes


















2














To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):



In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;



In[17]:= Do[Print[x], {x, Keys[assoc]}]



During evaluation of In[17]:= 0



During evaluation of In[17]:= 1



During evaluation of In[17]:= 2





share|improve this answer





























    6














    If you would like to map over the keys to transform them into something else, you can use KeyMap:



    a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
    
a // KeyMap[("newKey" <> #) &]
    
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)


    Otherwise, the good old Map will iterate over the values as if the structure were a list:



    a // Map[("newVal" <> ToString@#) &]
    
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)


    You should also look up KeyValueMap to see if that would make your task easier.



    Edit



    Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.






    share|improve this answer





















      Your Answer





      StackExchange.ifUsing("editor", function () {
      return StackExchange.using("mathjaxEditing", function () {
      StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
      StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
      });
      });
      }, "mathjax-editing");

      StackExchange.ready(function() {
      var channelOptions = {
      tags: "".split(" "),
      id: "387"
      };
      initTagRenderer("".split(" "), "".split(" "), channelOptions);

      StackExchange.using("externalEditor", function() {
      // Have to fire editor after snippets, if snippets enabled
      if (StackExchange.settings.snippets.snippetsEnabled) {
      StackExchange.using("snippets", function() {
      createEditor();
      });
      }
      else {
      createEditor();
      }
      });

      function createEditor() {
      StackExchange.prepareEditor({
      heartbeatType: 'answer',
      autoActivateHeartbeat: false,
      convertImagesToLinks: false,
      noModals: true,
      showLowRepImageUploadWarning: true,
      reputationToPostImages: null,
      bindNavPrevention: true,
      postfix: "",
      imageUploader: {
      brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
      contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
      allowUrls: true
      },
      onDemand: true,
      discardSelector: ".discard-answer"
      ,immediatelyShowMarkdownHelp:true
      });


      }
      });














      draft saved

      draft discarded


















      StackExchange.ready(
      function () {
      StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f187393%2fiterate-over-keys-of-association%23new-answer', 'question_page');
      }
      );

      Post as a guest















      Required, but never shown

























      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      2














      To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):



      In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
      

      
In[17]:= Do[Print[x], {x, Keys[assoc]}]
      

      
During evaluation of In[17]:= 0
      

      
During evaluation of In[17]:= 1
      

      
During evaluation of In[17]:= 2





      share|improve this answer


























        2














        To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):



        In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
        

        
In[17]:= Do[Print[x], {x, Keys[assoc]}]
        

        
During evaluation of In[17]:= 0
        

        
During evaluation of In[17]:= 1
        

        
During evaluation of In[17]:= 2





        share|improve this answer
























          2












          2








          2






          To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):



          In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
          

          
In[17]:= Do[Print[x], {x, Keys[assoc]}]
          

          
During evaluation of In[17]:= 0
          

          
During evaluation of In[17]:= 1
          

          
During evaluation of In[17]:= 2





          share|improve this answer












          To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):



          In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
          

          
In[17]:= Do[Print[x], {x, Keys[assoc]}]
          

          
During evaluation of In[17]:= 0
          

          
During evaluation of In[17]:= 1
          

          
During evaluation of In[17]:= 2






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Dec 5 at 19:41









          Jason B.

          47.7k387186




          47.7k387186























              6














              If you would like to map over the keys to transform them into something else, you can use KeyMap:



              a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
              
a // KeyMap[("newKey" <> #) &]
              
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)


              Otherwise, the good old Map will iterate over the values as if the structure were a list:



              a // Map[("newVal" <> ToString@#) &]
              
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)


              You should also look up KeyValueMap to see if that would make your task easier.



              Edit



              Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.






              share|improve this answer


























                6














                If you would like to map over the keys to transform them into something else, you can use KeyMap:



                a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
                
a // KeyMap[("newKey" <> #) &]
                
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)


                Otherwise, the good old Map will iterate over the values as if the structure were a list:



                a // Map[("newVal" <> ToString@#) &]
                
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)


                You should also look up KeyValueMap to see if that would make your task easier.



                Edit



                Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.






                share|improve this answer
























                  6












                  6








                  6






                  If you would like to map over the keys to transform them into something else, you can use KeyMap:



                  a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
                  
a // KeyMap[("newKey" <> #) &]
                  
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)


                  Otherwise, the good old Map will iterate over the values as if the structure were a list:



                  a // Map[("newVal" <> ToString@#) &]
                  
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)


                  You should also look up KeyValueMap to see if that would make your task easier.



                  Edit



                  Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.






                  share|improve this answer












                  If you would like to map over the keys to transform them into something else, you can use KeyMap:



                  a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
                  
a // KeyMap[("newKey" <> #) &]
                  
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)


                  Otherwise, the good old Map will iterate over the values as if the structure were a list:



                  a // Map[("newVal" <> ToString@#) &]
                  
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)


                  You should also look up KeyValueMap to see if that would make your task easier.



                  Edit



                  Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Dec 5 at 19:25









                  Shredderroy

                  1,4931115




                  1,4931115






























                      draft saved

                      draft discarded




















































                      Thanks for contributing an answer to Mathematica Stack Exchange!


                      • Please be sure to answer the question. Provide details and share your research!

                      But avoid …



                      • Asking for help, clarification, or responding to other answers.

                      • Making statements based on opinion; back them up with references or personal experience.


                      Use MathJax to format equations. MathJax reference.


                      To learn more, see our tips on writing great answers.





                      Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


                      Please pay close attention to the following guidance:


                      • Please be sure to answer the question. Provide details and share your research!

                      But avoid …



                      • Asking for help, clarification, or responding to other answers.

                      • Making statements based on opinion; back them up with references or personal experience.


                      To learn more, see our tips on writing great answers.




                      draft saved


                      draft discarded














                      StackExchange.ready(
                      function () {
                      StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f187393%2fiterate-over-keys-of-association%23new-answer', 'question_page');
                      }
                      );

                      Post as a guest















                      Required, but never shown





















































                      Required, but never shown














                      Required, but never shown












                      Required, but never shown







                      Required, but never shown

































                      Required, but never shown














                      Required, but never shown












                      Required, but never shown







                      Required, but never shown







                      -

                      Popular posts from this blog

                      Plaza Victoria

                      Image
                      Plaza Victoria Plaza Victoria en 2017 Otros nombres Plaza de La Victoria Localización El Almendral, Valparaíso, Chile Vías adyacentes Chacabuco, Molina, Plaza Victoria y Edwards Creación 1841 Metro Bellavista Ubicación 33°02′46″S 71°37′11″O  /  -33.04624167, -71.61980833 Coordenadas: 33°02′46″S 71°37′11″O  /  -33.04624167, -71.61980833 [editar datos en Wikidata] La Plaza Victoria , también llamada Plaza de la Victoria , [ 1 ] ​ es una plaza ubicada en el sector El Almendral del plan de la ciudad de Valparaíso, Chile, de importancia patrimonial, que incluye valiosas estatuas y especies vegetales. [ 2 ] ​ La plaza se creó como tal en la primera mitad del siglo XIX, tomando previamente los nombres de Plaza Nueva y Plaza de Orrego . Si bien desde sus inicios tuvo relevancia histórica, no fue sino a partir de fines de los años 1860 cuando comenzó a cobrar mayor importancia y se convirtió en uno de los principales centros sociales de l...
                      Read more

                      Puebla de Zaragoza

                      Image
                      Para otros usos de este término, véase Puebla (desambiguación). Heroica Puebla de Zaragoza Localidad De arriba a abajo de izquierda a derecha: Estrella de Puebla, Volcán Popocatépetl, Catedral de Puebla, Monumento a Ignacio Zaragoza, Estadio Cuauhtémoc, Angelópolis y Vista panorámica de la ciudad. Escudo Otros nombres: El relicario de América/ La ciudad de los Ángeles/ La Angelópolis Lema: Muy noble y muy leal ciudad de Puebla de los Ángeles Heroica Puebla de Zaragoza Localización de Heroica Puebla de Zaragoza en México Heroica Puebla de Zaragoza Localización de Heroica Puebla de Zaragoza en Puebla Mapa interactivo Coordenadas 19°03′05″N 98°13′04″O  /  19.051388888889, -98.217777777778 Coordenadas: 19°03′05″N 98°13′04″O  /  19.051388888889, -98.217777777778 Idioma oficial Español Entidad Localidad  • País   México  • Estado Puebla  • Municipio Puebla Presidente municipal Claudia Rivera Vivanc...
                      Read more

                      Musa

                      Image
                      Para el género de plantas, véase Musa (planta). Apolo y la Nueve Musas En la mitología griega, las musas (en griego antiguo μοῦσαι « mousai» ) son, según los escritores más antiguos, las divinidades inspiradoras de las Artes: cada una de ellas está relacionada con ramas artísticas y del conocimiento. Son hijas de Zeus y de Mnemósine, compañeras del séquito de Apolo, dios olímpico de la música y patrón de las bellas artes, quien tuvo romances con cada una de ellas, dejando descendientes. Bajaban a la tierra a susurrar ideas e inspirar a aquellos mortales que las invocaran. En la época más arcaica eran las ninfas inspiradoras de las fuentes, en las cuales eran adoradas. Finalmente, alrededor de los siglos VIII-VII a. C. [ 1 ] ​ prevaleció en todo el territorio de la Hélade la adoración de las nueve Musas, que son Calíope, Clío, Erato, Euterpe, Melpómene, Polimnia, Talía, Terpsícore y Urania. El culto a las musas era originalmente de Tracia y Beocia, y fueron de vital impo...
                      Read more