MATLAB: How tp join multiple matrices in one matrix

arraycell arraysfor loopif statementMATLABmatrix manipulation

Assume matrix A1, A2 and A3 as follows:
A1 = [
1  10  23
2  12  45
3  23  43
4  32  45
5  32  32
];
A2 = [
1  43  10
2  56  11
3  34  24
4  43  65
];
A3 = [
1  32  12
2  22  21
];
I want to join all of these matrices into one matrix A according to the unique ID number (first column in every matrix). For example, all row with ID = 1 in all three matrices should written first, then all ID = 2, then all ID = 3, and so on.
A = [
1  10  23
1  43  10
1  32  12
2  12  45
2  56  11
2  22  21
3  23  43
3  34  24
4  32  45
4  43  65
];

Best Answer

Use the sortrows function on the vertically concatenated matrices:
A = sortrows([A1; A2; A3], 1)
A =  
     1    10    23
     1    43    10
     1    32    12
     2    12    45
     2    56    11
     2    22    21
     3    23    43
     3    34    24
     4    32    45
     4    43    65
     5    32    32
Experiment to get the result you want. To eliminate the last row, the assignment becomes:
A = A(1:end-1,:);
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