How to create arrays from repeated matrix raws?

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Philippe Corner
Philippe Corner 2020-10-16
评论： Philippe Corner 2020-12-2
If we have a matrix A like:
A=[
1 2 3 4 5
1 2 8 9 10
1 2 13 14 15
11 12 16 27 18
11 12 19 29 21
11 12 22 23 24];
As you can see, the A(:,1:2), has repeated values each 3 raws. I would like to create "arrays" for each repeated raw values on A(:,1:2), and obtain a matrix B that creates new columns for the raws of repeated values like:
B=[
1 2 3 4 5 8 9 10 13 14 15
11 12 16 27 18 19 29 21 22 23 24];
Next image sumarizes the problem with colors for the final location of the raws creating 2 arrays for the repeated A(:,1:2).

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采纳的回答

Stephen23
Stephen23 2020-10-16
编辑：Stephen23 2020-10-16
>> A = [1,2,3,4,5;1,2,8,9,10;1,2,13,14,15;11,12,16,27,18;11,12,19,29,21;11,12,22,23,24]
A =
1 2 3 4 5
1 2 8 9 10
1 2 13 14 15
11 12 16 27 18
11 12 19 29 21
11 12 22 23 24
>> [U,X,Y] = unique(A(:,1:2),'rows');
>> F = @(r)reshape(A(Y==r,3:end).',1,[]);
>> C = arrayfun(F,1:max(Y),'uni',0);
>> M = [U,vertcat(C{:})]% optional (only works if number of columns is the same)
M =
1 2 3 4 5 8 9 10 13 14 15
11 12 16 27 18 19 29 21 22 23 24

更多回答（1 个）

Ameer Hamza
Ameer Hamza 2020-10-16
编辑：Ameer Hamza 2020-10-16
An alternative approach
A=[
1 2 3 4 5
1 2 8 9 10
1 2 13 14 15
11 12 16 27 18
11 12 19 29 21
11 12 22 23 24];
rows = find([1; any(diff(A(:,1:2)), 2)]);
B = [A(rows, 1:2) reshape(A(:,3:end).', (size(A,2)-2)*diff(rows(1:2)), []).'];
Result
>> B
B =
1 2 3 4 5 8 9 10 13 14 15
11 12 16 27 18 19 29 21 22 23 24

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