Sort rows of a matrix based on a specific array

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Amirhossein Moosavi
评论： madhan ravi 2020-7-13
Hi everyone,
Let us assum Matrix A and array B as follows:
A = [1 0 1
2 0 0
4 0 0
3 1 1
6 0 0
5 0 0]
B = [3 4 1]
Array B always include values stored in the first column of Matrix A. So, I want to sort rows of Matrix A based on Array B. Whatever comes first in Array B must come first in Matrix A. Moreover, I do not want to change the position of any other rows in Matrix A that their values (first column) do not exist in Array B.
Having said this, sorted version of Matrix A based on Array B will be as follows:
An = [3 1 1
2 0 0
4 0 0
1 0 1
6 0 0
5 0 0]
Would you please guide me what is the fastest way to do this?
Regards,
Amir

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采纳的回答

Stephen23
Stephen23 2020-7-13
编辑：Stephen23 2020-7-13
>> [X,Y] = ismember(A(:,1),B);
>> [~,Z] = sort(Y(X));
>> T = A(X,:);
>> A(X,:) = T(Z,:)
A =
3 1 1
2 0 0
4 0 0
1 0 1
6 0 0
5 0 0

更多回答（1 个）

madhan ravi
madhan ravi 2020-7-13
v = sort(B);
A([1, v(end)], :) = A([v(end), 1], :)
  2 个评论
Amirhossein Moosavi
Amirhossein Moosavi 2020-7-13
Thank you, but it does not work for some cases. Let us say Array B is as follows:
B = [3 4]
Then, Matrix A becomes like this (using your code):
A = [3 1 1
2 0 0
4 0 0
1 0 1
6 0 0
5 0 0]
While, Matrix A must have become as follows:
A = [1 0 1
2 0 0
3 1 1
4 0 0
6 0 0
5 0 0]

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