Eliminate empty elements from a list with a specific pattern












3












$begingroup$


I am really new in this patterns part of Mathematica. Basically what I need to do is eliminate null elements from a list but that has a specific name before the empty element. For example, my list is: 



list={"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"}


and I need to obtain 



list={"a12-b11-{1}", "d33-c22-{2}"}


The list was created using 



list =  Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 

        ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]  ]], 

        {i, 1, 4}, {j, 1, 4}], 1]


and for some values it writtes {} because there is not a value equal to $0.5$. Until now I have been able to do it term by term as 



list//."a11-b11-{}"-> Sequence


but the real list contains a lot of elements and could be almost impossible to do it that way to solve the problem. I think my main problem is that I am not sure how to specify the pattern search (something like " *-name " in gnu/linux). Is there a wise way to do this?. Thanks in advance.






list-manipulation filtering







share|improve this question











$endgroup$












  • $begingroup$
    Have a look at DeleteCases and StringMatchQ or StringContainsQ.
    $endgroup$
    – b.gatessucks
    yesterday










  • $begingroup$
    I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
    $endgroup$
    – Roman
    yesterday












  • $begingroup$
    @b.gatessucks Thank you, I will look those option in Mathematica.
    $endgroup$
    – mors
    yesterday










  • $begingroup$
    @Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
    $endgroup$
    – mors
    yesterday
















3












$begingroup$


I am really new in this patterns part of Mathematica. Basically what I need to do is eliminate null elements from a list but that has a specific name before the empty element. For example, my list is: 



list={"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"}


and I need to obtain 



list={"a12-b11-{1}", "d33-c22-{2}"}


The list was created using 



list =  Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 

        ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]  ]], 

        {i, 1, 4}, {j, 1, 4}], 1]


and for some values it writtes {} because there is not a value equal to $0.5$. Until now I have been able to do it term by term as 



list//."a11-b11-{}"-> Sequence


but the real list contains a lot of elements and could be almost impossible to do it that way to solve the problem. I think my main problem is that I am not sure how to specify the pattern search (something like " *-name " in gnu/linux). Is there a wise way to do this?. Thanks in advance.






list-manipulation filtering







share|improve this question











$endgroup$












  • $begingroup$
    Have a look at DeleteCases and StringMatchQ or StringContainsQ.
    $endgroup$
    – b.gatessucks
    yesterday










  • $begingroup$
    I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
    $endgroup$
    – Roman
    yesterday












  • $begingroup$
    @b.gatessucks Thank you, I will look those option in Mathematica.
    $endgroup$
    – mors
    yesterday










  • $begingroup$
    @Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
    $endgroup$
    – mors
    yesterday














3












3








3


1



$begingroup$


I am really new in this patterns part of Mathematica. Basically what I need to do is eliminate null elements from a list but that has a specific name before the empty element. For example, my list is: 



list={"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"}


and I need to obtain 



list={"a12-b11-{1}", "d33-c22-{2}"}


The list was created using 



list =  Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 

        ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]  ]], 

        {i, 1, 4}, {j, 1, 4}], 1]


and for some values it writtes {} because there is not a value equal to $0.5$. Until now I have been able to do it term by term as 



list//."a11-b11-{}"-> Sequence


but the real list contains a lot of elements and could be almost impossible to do it that way to solve the problem. I think my main problem is that I am not sure how to specify the pattern search (something like " *-name " in gnu/linux). Is there a wise way to do this?. Thanks in advance.






list-manipulation filtering







share|improve this question











$endgroup$




I am really new in this patterns part of Mathematica. Basically what I need to do is eliminate null elements from a list but that has a specific name before the empty element. For example, my list is: 



list={"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"}


and I need to obtain 



list={"a12-b11-{1}", "d33-c22-{2}"}


The list was created using 



list =  Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 

        ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]  ]], 

        {i, 1, 4}, {j, 1, 4}], 1]


and for some values it writtes {} because there is not a value equal to $0.5$. Until now I have been able to do it term by term as 



list//."a11-b11-{}"-> Sequence


but the real list contains a lot of elements and could be almost impossible to do it that way to solve the problem. I think my main problem is that I am not sure how to specify the pattern search (something like " *-name " in gnu/linux). Is there a wise way to do this?. Thanks in advance.






list-manipulation filtering




list-manipulation filtering






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited yesterday









Roman

4,89011130




4,89011130










asked yesterday









morsmors

496




496












  • $begingroup$
    Have a look at DeleteCases and StringMatchQ or StringContainsQ.
    $endgroup$
    – b.gatessucks
    yesterday










  • $begingroup$
    I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
    $endgroup$
    – Roman
    yesterday












  • $begingroup$
    @b.gatessucks Thank you, I will look those option in Mathematica.
    $endgroup$
    – mors
    yesterday










  • $begingroup$
    @Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
    $endgroup$
    – mors
    yesterday


















  • $begingroup$
    Have a look at DeleteCases and StringMatchQ or StringContainsQ.
    $endgroup$
    – b.gatessucks
    yesterday










  • $begingroup$
    I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
    $endgroup$
    – Roman
    yesterday












  • $begingroup$
    @b.gatessucks Thank you, I will look those option in Mathematica.
    $endgroup$
    – mors
    yesterday










  • $begingroup$
    @Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
    $endgroup$
    – mors
    yesterday
















$begingroup$
Have a look at DeleteCases and StringMatchQ or StringContainsQ.
$endgroup$
– b.gatessucks
yesterday




$begingroup$
Have a look at DeleteCases and StringMatchQ or StringContainsQ.
$endgroup$
– b.gatessucks
yesterday












$begingroup$
I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
$endgroup$
– Roman
yesterday






$begingroup$
I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
$endgroup$
– Roman
yesterday














$begingroup$
@b.gatessucks Thank you, I will look those option in Mathematica.
$endgroup$
– mors
yesterday




$begingroup$
@b.gatessucks Thank you, I will look those option in Mathematica.
$endgroup$
– mors
yesterday












$begingroup$
@Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
$endgroup$
– mors
yesterday




$begingroup$
@Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
$endgroup$
– mors
yesterday










2 Answers
2






active

oldest

votes


















7












$begingroup$

If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:



list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};

Select[list, Not@*StringMatchQ[__ ~~ "{}"]]



{"a12-b11-{1}", "d33-c22-{2}"}




You could also Select before making the strings:



L = DeleteCases[

      Flatten[

        Table[

          {namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]},

          {i, 4}, {j, 4}],

        1],

      {_, _, {}}];


and then make these into strings:



StringRiffle[ToString /@ #, "-"] & /@ L


I can't check this because you didn't supply functioning code.






share|improve this answer











$endgroup$













  • $begingroup$
    Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], {i, 1, 4}, {j, 1, 4}], 1] '
    $endgroup$
    – mors
    yesterday





















1












$begingroup$

In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using



list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};

Select[list, Not@*StringEndsQ["{}"]]


instead.






share|improve this answer









$endgroup$














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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    7












    $begingroup$

    If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:



    list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
    
Select[list, Not@*StringMatchQ[__ ~~ "{}"]]



    {"a12-b11-{1}", "d33-c22-{2}"}




    You could also Select before making the strings:



    L = DeleteCases[
    
      Flatten[
    
        Table[
    
          {namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]},
    
          {i, 4}, {j, 4}],
    
        1],
    
      {_, _, {}}];


    and then make these into strings:



    StringRiffle[ToString /@ #, "-"] & /@ L


    I can't check this because you didn't supply functioning code.






    share|improve this answer











    $endgroup$













    • $begingroup$
      Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], {i, 1, 4}, {j, 1, 4}], 1] '
      $endgroup$
      – mors
      yesterday


















    7












    $begingroup$

    If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:



    list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
    
Select[list, Not@*StringMatchQ[__ ~~ "{}"]]



    {"a12-b11-{1}", "d33-c22-{2}"}




    You could also Select before making the strings:



    L = DeleteCases[
    
      Flatten[
    
        Table[
    
          {namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]},
    
          {i, 4}, {j, 4}],
    
        1],
    
      {_, _, {}}];


    and then make these into strings:



    StringRiffle[ToString /@ #, "-"] & /@ L


    I can't check this because you didn't supply functioning code.






    share|improve this answer











    $endgroup$













    • $begingroup$
      Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], {i, 1, 4}, {j, 1, 4}], 1] '
      $endgroup$
      – mors
      yesterday
















    7












    7








    7





    $begingroup$

    If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:



    list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
    
Select[list, Not@*StringMatchQ[__ ~~ "{}"]]



    {"a12-b11-{1}", "d33-c22-{2}"}




    You could also Select before making the strings:



    L = DeleteCases[
    
      Flatten[
    
        Table[
    
          {namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]},
    
          {i, 4}, {j, 4}],
    
        1],
    
      {_, _, {}}];


    and then make these into strings:



    StringRiffle[ToString /@ #, "-"] & /@ L


    I can't check this because you didn't supply functioning code.






    share|improve this answer











    $endgroup$



    If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:



    list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
    
Select[list, Not@*StringMatchQ[__ ~~ "{}"]]



    {"a12-b11-{1}", "d33-c22-{2}"}




    You could also Select before making the strings:



    L = DeleteCases[
    
      Flatten[
    
        Table[
    
          {namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1]},
    
          {i, 4}, {j, 4}],
    
        1],
    
      {_, _, {}}];


    and then make these into strings:



    StringRiffle[ToString /@ #, "-"] & /@ L


    I can't check this because you didn't supply functioning code.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited yesterday

























    answered yesterday









    RomanRoman

    4,89011130




    4,89011130












    • $begingroup$
      Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], {i, 1, 4}, {j, 1, 4}], 1] '
      $endgroup$
      – mors
      yesterday




















    • $begingroup$
      Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], {i, 1, 4}, {j, 1, 4}], 1] '
      $endgroup$
      – mors
      yesterday


















    $begingroup$
    Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], {i, 1, 4}, {j, 1, 4}], 1] '
    $endgroup$
    – mors
    yesterday






    $begingroup$
    Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], {i, 1, 4}, {j, 1, 4}], 1] '
    $endgroup$
    – mors
    yesterday













    1












    $begingroup$

    In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using



    list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
    
Select[list, Not@*StringEndsQ["{}"]]


    instead.






    share|improve this answer









    $endgroup$


















      1












      $begingroup$

      In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using



      list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
      
Select[list, Not@*StringEndsQ["{}"]]


      instead.






      share|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using



        list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
        
Select[list, Not@*StringEndsQ["{}"]]


        instead.






        share|improve this answer









        $endgroup$



        In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using



        list = {"a11-b11-{}", "a12-b11-{1}", "c11-d22-{}", "d33-c22-{2}"};
        
Select[list, Not@*StringEndsQ["{}"]]


        instead.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered yesterday









        rcollyerrcollyer

        28.6k674166




        28.6k674166






























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            Gregoriusmis

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            Een afbeelding van de Gregoriusmis uit een getijdenboek gemaakt in de zuidelijke Nederlanden tussen 1500 en 1525 Gregoriusmis, Meester van het Akense Altaar, ca. 1500-1525. Collectie Museum Catharijneconvent De Gregoriusmis of de Mis van Sint Gregorius is een motief in katholieke kunst, dat het eerst verscheen in de late Middeleeuwen en dat nog steeds werd gebruikt tijdens de contrareformatie. Paus Gregorius I (ca. 540-604) is afgebeeld, de H. Mis opdragend, terwijl Christus als de Man van Smarten verschijnt op het altaar dat voor Sint Gregorius staat. Volgens de legende had St. Gregorius gebeden om een teken voor een betwijfelaar van de transsubstantiatieleer, waarop de lijdende Christus tijdens het opdragen van de Mis verscheen om hem te overtuigen en waarbij zijn bloed in de altaarkelk liep. Vaak zijn ook de passiewerktuigen afgebeeld. Zie de categorie Mass of Saint Gregory van Wikimedia Commons voor mediabestanden over dit onderwerp. This page is onl
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