MATLAB: How to replace values in a matrix

matrixmatrix manipulationreplace

Hello everyone, I am new in matlab and I need help please.
I have a matrix A that contains probability distribution( size : 7*8).there is the matrix :
 A=[ 0.2 0.07 0.25 0.87 0.09 0.14 0.8 0.3;
     0.1 0.5 0.25 0.14 0.98 0.025 0.58 0.11;
     0.001 0.25 0.88 0.21 0.03 0.25 0.58 0.25;
     0.26 0.58 0.001 0.06 0.9 0.58 0.44 0.15;
     0.12 0.58 0.16 0.08 0.15 0.47 0.33 0.15;
     0.15 0.22 0.3 0.14 0.01 0.99 0.77 0.55;
     0.003 0.25 0.14 0.99 0.005 0.85 0.26 0.003; 
   ];
I have also a matrix B (size 7*4) that contains such A probabilities and matrix C (size 7*4) that contains positions.
 B=[ 0.25 0.55 0.15 0.02;
     0.001 0.25 0.33 0.04;
     0.2 0.3 0.11 0.58;
     0.25 0.14 0.77 0.69;
     0.88 0.59 0.58 0.001;
     0.02 0.3 0.7 0.8;
     0.3 0.9 0.66 0.11;]
C= [ 8 2 4 1
     1 2 3 4
     7 5 2 8
     1 2 3 4
     2 4 3 7
     1 5 6 7
     2 8 4 1]
My goal is to replace values in A with values in the matrix B according to the position in C, I will have as result this matrix (size 7*8) :
 NewA=[ 0.02 0.55 0.25 0.15 0.09 0.14 0.08 0.25
        0.001 0.25 0.33 0.04 0.98 0.025 0.58 0.11
        0.001 0.11 0.88 0.21 0.3 0.25 0.2 0.58
        0.25 0.14 0.77 0.69 0.9 0.58 0.44 0.15
        0.12 0.88 0.58 0.59  0.15  0.047 0.001 0.15
        0.02 0.22 0.3 0.14 0.21 0.7 0.8 0.55
        0.11 0.3 0.14 0.66 0.005 0.85 0.26 0.9]
Please, any idea, How Can I do it? and thanks in advance

Best Answer

Try a simple for loop:
A=[ 0.2 0.07 0.25 0.87 0.09 0.14 0.8 0.3;
  0.1 0.5 0.25 0.14 0.98 0.025 0.58 0.11;
  0.001 0.25 0.88 0.21 0.03 0.25 0.58 0.25;
  0.26 0.58 0.001 0.06 0.9 0.58 0.44 0.15;
  0.12 0.58 0.16 0.08 0.15 0.47 0.33 0.15;
  0.15 0.22 0.3 0.14 0.01 0.99 0.77 0.55;
  0.003 0.25 0.14 0.99 0.005 0.85 0.26 0.003;
  ];
B=[ 0.25 0.55 0.15 0.02;
  0.001 0.25 0.33 0.04;
  0.2 0.3 0.11 0.58;
  0.25 0.14 0.77 0.69;
  0.88 0.59 0.58 0.001;
  0.02 0.3 0.7 0.8;
  0.3 0.9 0.66 0.11;]
C= [ 8 2 4 1
  1 2 3 4
  7 5 2 8
  1 2 3 4
  2 4 3 7
  1 5 6 7
  2 8 4 1]
[rows, columns] = size(B)
newA = A; % Initialize.
for row = 1 : rows
  newA(row, C(row,:)) = B(row, :);
end
newA % Print in command window to verify
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