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
    12 hours ago










  • $begingroup$
    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
    12 hours ago












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










  • $begingroup$
    @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
    12 hours ago
















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
    12 hours ago










  • $begingroup$
    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
    12 hours ago












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










  • $begingroup$
    @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
    12 hours ago














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 7 hours ago









Roman

4,66511128




4,66511128










asked 13 hours ago









morsmors

496




496












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










  • $begingroup$
    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
    12 hours ago












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










  • $begingroup$
    @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
    12 hours ago


















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










  • $begingroup$
    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
    12 hours ago












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










  • $begingroup$
    @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
    12 hours ago
















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




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












$begingroup$
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
12 hours ago






$begingroup$
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
12 hours ago














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




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












$begingroup$
@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
12 hours ago




$begingroup$
@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
12 hours ago










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
    12 hours ago





















0












$begingroup$

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
      12 hours ago


















    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
      12 hours ago
















    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 8 hours ago

























    answered 12 hours ago









    RomanRoman

    4,66511128




    4,66511128












    • $begingroup$
      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
      12 hours ago




















    • $begingroup$
      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
      12 hours ago


















    $begingroup$
    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
    12 hours ago






    $begingroup$
    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
    12 hours ago













    0












    $begingroup$

    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









    $endgroup$


















      0












      $begingroup$

      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









      $endgroup$
















        0












        0








        0





        $begingroup$

        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 6 hours ago









        rcollyerrcollyer

        28.6k674166




        28.6k674166






























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            8-я гвардейская общевойсковая ордена Ленина армия Награды: Войска: РККА → Советская армия → СВ России Род войск: Формирование: 1943 Расформирование (преобразование): 1992 Предшественник: 62-я армия (1942—43) → 8-я гвардейская общевойсковая армия (1943—92) → 8-й гвардейский армейский корпус (1992—98) Боевой путь Изюм-Барвенковская операция Донбасская операция Запорожская операция Битва за Днепр Днепропетровская операция Березнеговато-Снигирёвская операция Одесская операция Люблин-Брестская операция Варшавско-Познанская операция Восточно-Померанская операция Берлинская наступательная операция У этого термина существуют и другие значения, см. 8-я армия. Фотография Гвардейского Красного Знамени (лицевая сторона) 8-й гвардейской армии , образца 1943 года. Фотография Гвардейского Красного Знамени (оборотная сторона) 8-й гвардейской армии , образца 1943 года. 8-я гвардейская общевойсковая ордена Ленина армия  — гвардейское фор...
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            Алькесар

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            Муниципалитет Алькесар Alquézar Герб 42°10′16″ с. ш. 0°01′27″ в. д. H G Я O L Страна Испания   Испания Автономное сообщество Арагон Провинция Уэска Комарка Сомонтано-де-Барбастро Алькальд Хосе Марияно Альтемир Ласкорс (ИСРП) История и география Площадь 32,36 км² Высота НУМ 660 м Часовой пояс UTC+1, летом UTC+2 Население Население 313 человек ( 2010 ) Плотность 9,92 чел./км² Этнохороним alquezarano/-a Цифровые идентификаторы Телефонный код +34 974 Почтовые индексы 22112 Автомобильный код HU alquezar.org   (исп.) Показать/скрыть карты Алькесар Алькесар Алькесар  Аудио, фото и видео на Викискладе Алькесар (исп.  Alquézar ) — муниципалитет в Испании, входит в провинцию Уэска, в составе автономного сообщества Арагон. Муниципалитет находится в составе района (комарки) Сомонтано-де-Барбастро. Занимает площадь 32,36 км². Население — 321 челове...
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