Multiple loops to build structure?

Question

Joe 2024-2-18

1
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2083638-multiple-loops-to-build-structure

评论： Stephen23 2024-2-19

I have k=6 matrices of sound data that I am trying to loop thru to create structures for plotting.

Each matrix has 9 channels: X1-X3, Y1-Y3, Z1-Z3. Each channel has 5 columns of data. The first column is time, and the next 4 columns are sound data: a hi and lo set of + and –data.

I want to create 6 structures that contain data from the 6 groups with some manual inputs for naming.

The structures need to have a group, name, hi or lo, positive or negative, and then the data that gets read in from columns.

Can someone show me a faster and easier way of doing what I’m doing this? Especially because it is so repetitive. Below is my futile approach to setting this up with an example of how I plan to plot it.

%group matrix = k=1

g(1).x1.group = 'Group 1:';

g(1).x1.name = 'North';

g(1).x1.ch1.name.pos = 'Channel Hi';

g(1).x1.ch1.name.neg = 'Channel Lo';

g(1).x1.ch1.pos = [group(1)(:,1),group(1)(:,2)];

g(1).x1.ch1.neg = [group(1)(:,1),group(1)(:,3)];

g(1).x1.ch2.name.pos = 'Channel Hi';

g(1).x1.ch2.name.neg = 'Channel Lo';

g(1).x1.ch2.pos = [group(1)(:,1),group(1)(:,4)];

g(1).x1.ch2.neg = [group(1)(:,1),group(1)(:,5)];

%

%Group 2 X data

g(1).x2.group = 'Group 1:';

g(1).x2.name = 'East';

g(1).x2.ch1.name.pos = 'Channel Hi';

g(1).x2.ch1.name.neg = 'Channel Lo';

g(1).x2.ch1.pos = [group(1)(:,1),group(1)(:,6)];

g(1).x2.ch1.neg = [group(1)(:,1),group(1)(:,7)];

g(1).x2.ch2.name.pos = 'Channel Hi';

g(1).x2.ch2.name.neg = 'Channel Lo';

g(1).x2.ch2.pos = [group(1)(:,1),group(1)(:,8)];

g(1).x2.ch2.neg = [group(1)(:,1),group(1)(:,9)];

%Group 3 X data

g(1).x3.group = 'Group 1:';

g(1).x3.name = 'West';

g(1).x3.ch1.name.pos = 'Channel Hi';

g(1).x3.ch1.name.neg = 'Channel Lo';

g(1).x3.ch1.pos = [group(1)(:,1),group(1)(:,10)];

g(1).x3.ch1.neg = [group(1)(:,1),group(1)(:,11)];

g(1).x3.ch2.name.pos = 'Channel Hi';

g(1).x3.ch2.name.neg = 'Channel Lo';

g(1).x3.ch2.pos = [group(1)(:,1),group(1)(:,12)];

g(1).x3.ch2.neg = [group(1)(:,1),group(1)(:,13)];

%group 2

g(2).x1.group = 'Group 2:';

g(2).x1.name = 'North';

g(2).x1.ch1.name.pos = 'Channel Hi';

g(2).x1.ch1.name.neg = 'Channel Lo';

g(21).x1.ch1.pos = [group(2)(:,1),group(2)(:,2)];

.

%and so on, and so on

figure()

for k = 1:4

legStr = sprintf( '%s', g(k).x1.ch1.name.pos);

loglog(g(k).x1.ch1.pos(:,1), g(k).x1.ch1.pos(:,2), 'k-', 'Displayname', legStr); hold on; grid minor;

legStr = sprintf( '%s', g(k).x1.ch2.name.neg);

loglog(g(k).x1.ch2.neg(:,1), g(k).x2.ch2.neg(:,2), 'r-', 'Displayname', legStr);

end

2 个评论
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VBBV 2024-2-19

编辑：VBBV 2024-2-19

在 MATLAB Online 中打开

May be you can extend the code which you plotted at the end by using additional for loop as shown below

for k = 1:6 % for groups
    for J = 1:3  % for channels
         g(k).x(J).group = 'Group 1:';
         g(k).x(J).ch1.name.pos = 'Channel Hi'
         g(k).x(J).ch1.name.neg = 'Channel Lo';         
         g(k).x(J).name = 'North';          
         
    end
end

Stephen23 2024-2-19

"Can someone show me a faster and easier way of doing what I’m doing this? Especially because it is so repetitive."

Use indexing.

Avoid putting meta-data (e.g. pseudo-indices) into the fieldnames (or names of variables).

Computers are really only very good at repeating very simple tasks in loops. So when you sit and copy-and-paste lots of lines of code like that you are just doing the computer's job for it. Much better: use indexing, let the computer do the looping.

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Answer 1

Sulaymon Eshkabilov 2024-2-19

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2083638-multiple-loops-to-build-structure#answer_1411368

在 MATLAB Online 中打开

It can be done somewhat what like this one:

GN = {'Group 1:'; 'Group 2:'; 'Group 3:'};
NA = {'North'; 'East'; 'West'];
for ii = 1:3
        g(ii).x1.group = GN{ii};
        g(ii).x2.group = GN{ii};
        g(ii).x3.group = GN{ii};
        g(ii).x1.name = NA{ii};
        g(ii).x2.name = NA{ii};
        g(ii).x3.name = NA{ii};
        ...
end