Split an array in python using indexes from a list









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-2
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I have a 2d array of size 3 by 7 in numpy:



[[1 2 3 4 5 6 7]
[4 5 6 7 8 9 0] 
[2 3 4 5 6 7 8]]


I also have a list that contains indexes of splitting points:



[1, 3]


Now, I want to split the array using the indexes in the list such that I get:



[[1 2]
[4 5]
[2 3]]

[[ 2 3 4]
[5 6 7]
[3 4 5]]

[[ 4 5 6 7]
[7 8 9 0]
[5 6 7 8]]


How can I do this in python?






python python-3.x list numpy indexing







share|improve this question



























    up vote
    -2
    down vote

    favorite












    I have a 2d array of size 3 by 7 in numpy:



    [[1 2 3 4 5 6 7]
    [4 5 6 7 8 9 0] 
    [2 3 4 5 6 7 8]]


    I also have a list that contains indexes of splitting points:



    [1, 3]


    Now, I want to split the array using the indexes in the list such that I get:



    [[1 2]
    [4 5]
    [2 3]]

    [[ 2 3 4]
    [5 6 7]
    [3 4 5]]

    [[ 4 5 6 7]
    [7 8 9 0]
    [5 6 7 8]]


    How can I do this in python?






    python python-3.x list numpy indexing







    share|improve this question

























      up vote
      -2
      down vote

      favorite









      up vote
      -2
      down vote

      favorite











      I have a 2d array of size 3 by 7 in numpy:



      [[1 2 3 4 5 6 7]
      [4 5 6 7 8 9 0] 
      [2 3 4 5 6 7 8]]


      I also have a list that contains indexes of splitting points:



      [1, 3]


      Now, I want to split the array using the indexes in the list such that I get:



      [[1 2]
      [4 5]
      [2 3]]

      [[ 2 3 4]
      [5 6 7]
      [3 4 5]]

      [[ 4 5 6 7]
      [7 8 9 0]
      [5 6 7 8]]


      How can I do this in python?






      python python-3.x list numpy indexing







      share|improve this question















      I have a 2d array of size 3 by 7 in numpy:



      [[1 2 3 4 5 6 7]
      [4 5 6 7 8 9 0] 
      [2 3 4 5 6 7 8]]


      I also have a list that contains indexes of splitting points:



      [1, 3]


      Now, I want to split the array using the indexes in the list such that I get:



      [[1 2]
      [4 5]
      [2 3]]

      [[ 2 3 4]
      [5 6 7]
      [3 4 5]]

      [[ 4 5 6 7]
      [7 8 9 0]
      [5 6 7 8]]


      How can I do this in python?






      python python-3.x list numpy indexing




      python python-3.x list numpy indexing






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited 2 days ago









      jpp

      79.8k184695




      79.8k184695










      asked 2 days ago









      mrbright

      224




      224






















          1 Answer
          1






          active

          oldest

          votes

















          up vote
          2
          down vote



          accepted










          You can use a list comprehension with slicing, using zip to extract indices pairwise.



          A = np.array([[1, 2, 3, 4, 5, 6, 7],
           [4, 5, 6, 7, 8, 9, 0],
           [2, 3, 4, 5, 6, 7, 8]])

          idx = [1, 3]
          idx = [0] + idx + [A.shape[1]]

          res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

          print(*res, sep='n'*2)

          [[1 2]
           [4 5]
           [2 3]]

          [[2 3 4]
           [5 6 7]
           [3 4 5]]

          [[4 5 6 7]
           [7 8 9 0]
           [5 6 7 8]]





          share|improve this answer




















          • Thank you @jpp, It worked
            – mrbright
            2 days ago










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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          2
          down vote



          accepted










          You can use a list comprehension with slicing, using zip to extract indices pairwise.



          A = np.array([[1, 2, 3, 4, 5, 6, 7],
           [4, 5, 6, 7, 8, 9, 0],
           [2, 3, 4, 5, 6, 7, 8]])

          idx = [1, 3]
          idx = [0] + idx + [A.shape[1]]

          res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

          print(*res, sep='n'*2)

          [[1 2]
           [4 5]
           [2 3]]

          [[2 3 4]
           [5 6 7]
           [3 4 5]]

          [[4 5 6 7]
           [7 8 9 0]
           [5 6 7 8]]





          share|improve this answer




















          • Thank you @jpp, It worked
            – mrbright
            2 days ago














          up vote
          2
          down vote



          accepted










          You can use a list comprehension with slicing, using zip to extract indices pairwise.



          A = np.array([[1, 2, 3, 4, 5, 6, 7],
           [4, 5, 6, 7, 8, 9, 0],
           [2, 3, 4, 5, 6, 7, 8]])

          idx = [1, 3]
          idx = [0] + idx + [A.shape[1]]

          res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

          print(*res, sep='n'*2)

          [[1 2]
           [4 5]
           [2 3]]

          [[2 3 4]
           [5 6 7]
           [3 4 5]]

          [[4 5 6 7]
           [7 8 9 0]
           [5 6 7 8]]





          share|improve this answer




















          • Thank you @jpp, It worked
            – mrbright
            2 days ago












          up vote
          2
          down vote



          accepted







          up vote
          2
          down vote



          accepted






          You can use a list comprehension with slicing, using zip to extract indices pairwise.



          A = np.array([[1, 2, 3, 4, 5, 6, 7],
           [4, 5, 6, 7, 8, 9, 0],
           [2, 3, 4, 5, 6, 7, 8]])

          idx = [1, 3]
          idx = [0] + idx + [A.shape[1]]

          res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

          print(*res, sep='n'*2)

          [[1 2]
           [4 5]
           [2 3]]

          [[2 3 4]
           [5 6 7]
           [3 4 5]]

          [[4 5 6 7]
           [7 8 9 0]
           [5 6 7 8]]





          share|improve this answer












          You can use a list comprehension with slicing, using zip to extract indices pairwise.



          A = np.array([[1, 2, 3, 4, 5, 6, 7],
           [4, 5, 6, 7, 8, 9, 0],
           [2, 3, 4, 5, 6, 7, 8]])

          idx = [1, 3]
          idx = [0] + idx + [A.shape[1]]

          res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

          print(*res, sep='n'*2)

          [[1 2]
           [4 5]
           [2 3]]

          [[2 3 4]
           [5 6 7]
           [3 4 5]]

          [[4 5 6 7]
           [7 8 9 0]
           [5 6 7 8]]






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 2 days ago









          jpp

          79.8k184695




          79.8k184695











          • Thank you @jpp, It worked
            – mrbright
            2 days ago
















          • Thank you @jpp, It worked
            – mrbright
            2 days ago















          Thank you @jpp, It worked
          – mrbright
          2 days ago




          Thank you @jpp, It worked
          – mrbright
          2 days ago

















           

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