How can I replace matrix with random generated number (int) and position?

Question

Noru 2013-1-21

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/59364-how-can-i-replace-matrix-with-random-generated-number-int-and-position

Hello,

I'am trying to combine 2 matrix, I have 1 matrix with fix number, column, and rows. The other one consist of 2 column matrix with random rows (this matrix more little than matrix 1) and I have to generate it first, randomly. For the example is :

matrix 1 : X   Y   Z
           1  0.0  2
           2  0.0  5
           3  0.0  1
           4  0.0  3
           5  0.0  0
matrix 2 : A   B
           1   0
           2   8
           4   6

Based on the example, column A used to replace column X and column B used to replace column Z. The value of column A show us where to replace the value of column B in Z.

When the value of A is 2, then the value of Z in row 2 which is '5' replace by '8' as the value of B.
When the value of A is 4, then the value of Z in row 4 which is '3' replace by '6' as the value of B.
But there is an exception, the value of column Z row 1 should not be changed, so when the generated value of A is 1, the value of Z in row 1 which is '2' should not replace by the value of column B and still worth '2'.
This program will loop with 100 of maximum iterations, and in every iteration, matrix 2 will generated randomly.

Does anyone have the solution..?

Thanks.

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Walter Roberson 2013-1-21

In Matrix 2, can there be multiple rows with the same A but different B?

Noru 2013-1-28

I don't really understand with function of multiple rows with the same A but different B.. But if you think have a solution, it will very welcome and thank you.. :)

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Answer 1

Andrei Bobrov 2013-1-21

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/59364-how-can-i-replace-matrix-with-random-generated-number-int-and-position#answer_71836

在 MATLAB Online 中打开

eg

A = [(1:20)', zeros(20,1), randi([0 20],20,1)];
for jj = 1:100
    n = rand(20,1) > rand();     %
    B0 = randi([0 10],nnz(n),1); %  random generation of the matrix 2 (B)
    B = [A(n,1), B0];            %
      t = B(:,1) > 1;
      A(ismember(A(:,1),B(t,1)),3) = B(t,2);
  end