How to merger multiple .mat files consists of 2D matrix into 3D matrix

Hi everyone, I have 7 .mat files, which each files consists of 2D matrix (2048x22). I want to merger it into 2048x22x7. I already done it, but the value inside the matrix is 0, -0 like the image below.

I want to make layer like the image below.

I attach my .mat files, so anyone could see the matrix inside the matfiles. Could anyone help me? Thank you.

[Simon Chan]

The values of most of the data are close to zero and hence it shows 0.0000 or -0.0000 when you display them. It seems to be normal.

[Stephen23]

As Simon Chan already commented, most of your data are close to zero.

So it is not really a surprise, then when displayed to four decimal places, you will see a lot of zeros.

S = load('01.mat')

S = struct with fields:
    data_matrix: [2048×22 double]

histogram(S.data_matrix(:))

Note that you can change the display format, and in the settings also the format used for the variable viewer.

"but the value inside the matrix is 0, -0"

In MATLAB a displayed 0 only ever means that the value is exactly zero. If the number has trailing zeros, like your data, then we know that the value is not exactly zero (even if the non-zero digits are too small to be shown with the current format precision).

Answer 1

[Stephen23]

Using the files from your comment, and assuming that the filenames all use sufficient leading zeros:

D = '.'; % absolute or relative path to where the files are saved.
S = dir(fullfile(D,'*.mat'));
N = numel(S);
for k = 1:N
    F = fullfile(D,S(k).name);
    T  = load(F);
    S(k).data = T.data_matrix; 
end
A = cat(3,S.data);
size(A)

ans = 1×3

2048 22 4

[college student]

Right, I re-check my data and the value inside each matrix are close to zero. How to plot them in 3d figure/volume figure?

[Stephen23]

https://www.mathworks.com/help/matlab/ref/slice.html

https://www.mathworks.com/help/matlab/ref/plot3.html

https://www.mathworks.com/help/matlab/ref/scatter3.html