Load data with varying names

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Jeroen van Bemmel
编辑： Jeroen van Bemmel 2022-2-1
I have data files (.mat format) which consists of 140 files which only vary in their name which a increasing number:
cam_0_C182_0000001.mat
cam_0_C182_0000002.mat
...
cam_0_C182_0000140.mat
From those files (which are matlab structures, and i am intrested in a single value from a matrix within that structure.
How can i construct a loop which automatically loads all the files, and gets that one value, and places them in a new array?
for i = 1:140
Structure = cam_0_C182_0000('i').mat;
Output(i) = Structure.X(6,73); % get value (6,73) from matrix X, within the structure
end
My problem mainly is that i am not sure how to convert the numbers i from the loop to string value for the .m files in the folder, furthermore does 1 have to be translated to string (001), 45 to (045) and 101 to (101), so how do i format this number correctly to place zeros in front of the number if lover then 10, or then 100?
Thanks in advance
  1 个评论
Stephen23
Stephen23 2022-2-1
编辑：Stephen23 2022-2-1
Your description is unclear: "I have data files (.m format) which consists of 140 files which only vary in their name which a increasing number: cam_0_C182_0000001.mat...". So what do you actually have saved in that folder:
  • M-files (.m, as you wrote in your description) which are text files containing code.
  • Mat files (.mat, as your examples show) which are binary files containing data.
Mixing things up makes it hard for us to know what you are actually doing.

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Stephen23
Stephen23 2022-2-1
编辑：Stephen23 2022-2-1
The MATLAB documentation explains how:
https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html
The easy approach is to use DIR:
P = 'absolute or relative path to where the files are saved':
S = dir(fullfile(P,'cam_0_C182_0*.mat'));
N = numel(S);
V = nan(1,N);
for k = 1:N
D = load(fullfile(P,S(k).name));
V(k) = D.X(6,73);
end
Else use SPRINTF if you really want to generate the filenames from numerics:
N = 140;
V = nan(1,N);
for k = 1:N;
F = sprintf('cam_0_C182_%07d.mat',k);
D = load(fullfile(P,F));
V(k) = D.X(6,73);
end
In both cases you will need to LOAD the filedata (the syntax you show in your question does not exist).
  1 个评论
Jeroen van Bemmel
Jeroen van Bemmel 2022-2-1
Thank you so much!
much less code then i was anticipating.
you are the mvp ;)

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