transform an empty matrix '0x0 double' into a matrix '0x2 double'
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Alberto Acri
el 20 de Jul. de 2023
Comentada: Bruno Luong
el 20 de Jul. de 2023
Hello! How can I transform an empty matrix '0x0 double' into a matrix '0x2 double' as in the figure?
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1438573/image.png)
For example in my case, I have a cell 'test_p'. Rows 3,4,5 (0x0 double) should become like rows 1 and 2 (0x2 double).
test_p = importdata("test_p.mat");
data_0x2_double = test_p{1, 1};
data_0x0_double = test_p{3, 1};
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Bruno Luong
el 20 de Jul. de 2023
Editada: Bruno Luong
el 20 de Jul. de 2023
test_p = importdata("test_p.mat")
ir = cellfun('size',test_p,1)==0 & cellfun('size',test_p,2)==0
test_p(ir) = {zeros(0,2)}
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Más respuestas (2)
Steven Lord
el 20 de Jul. de 2023
Since a 0-by-0 array and a 0-by-2 array have the same number of elements you can reshape one into the other.
A = zeros(0, 0)
B = reshape(A, [0 2])
C = reshape(B, 0, 0)
whos A B C
3 comentarios
Steven Lord
el 20 de Jul. de 2023
Your code below made an assumption about the user's data, one that's likely valid (and is valid WRT the original question) but in some cases may not be.
A = zeros(0, 0, 'single');
B = reshape(A, [0 2]);
C = zeros(0, 2);
whos A B C
B and C are different classes. You could modify the call that creates C to always create it 'like' A or with the same type as A, but reshape will not change the type and is shorter than either of the calls that create C1 or C2 below.
C1 = zeros(0, 2, 'like', A)
C2 = zeros(0, 2, class(A))
Bruno Luong
el 20 de Jul. de 2023
OK in short you want to preserve the class of the data with reshape.
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