How to extract rows from a large number of rows that matchs a unique element in the column

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Young Lee 2018-10-21

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/425149-how-to-extract-rows-from-a-large-number-of-rows-that-matchs-a-unique-element-in-the-column

评论： madhan ravi 2018-10-21

       ID             Test1         Test2        Test 3                                                                               
       1               10.1          100         100
       2               200           0.1         400
       3               50            80          20.123     
       4               1000          2000        3000
       5               0              1          10.987

say i have a column vector a = [ 20.123 10.987]' my desired result would be ans=

       3        50       80          20.123  
       5         0        1          10.987

I have a set of column vector a = (42x1)' and wish to filter through a large number of rows in a matrix to extract rows from specific column which matches with one element of my column vector. can we use logical indexing for this?

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Walter Roberson 2018-10-21

Ah. When I was reading the question on my phone, I could not see the additional columns in the matrix.

madhan ravi 2018-10-21

Ok sir Walter

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采纳的回答

madhan ravi 2018-10-21

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/425149-how-to-extract-rows-from-a-large-number-of-rows-that-matchs-a-unique-element-in-the-column#answer_342461

编辑：madhan ravi 2018-10-21

在 MATLAB Online 中打开

>> matrix =        [  1               10.1          100         100
                      2               200           0.1         400
                      3               50            80          20.123     
                      4               1000          2000        3000
                      5               0              1          10.987 ];
                  a = [ 20.123 10.987]
                  idx = ismember(matrix,a);
                  [idx1,~]= find(idx==1);
                  myreesult = matrix((idx1),:)
a =
     20.1230   10.9870
myresult =
      3.0000   50.0000   80.0000   20.1230
      5.0000         0    1.0000   10.9870
>>