transform an empty matrix '0x0 double' into a matrix '0x2 double'
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Alberto Acri
le 20 Juil 2023
Commenté : Bruno Luong
le 20 Juil 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
le 20 Juil 2023
Modifié(e) : Bruno Luong
le 20 Juil 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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Steven Lord
le 20 Juil 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
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Steven Lord
le 20 Juil 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))
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