Saving a Structured Array (containing plot parameters) to a mat file

4 次查看（过去 30 天）
Jason
Jason 2024-6-24
评论： Jason 2024-6-24
Hi, Im trying to save plot data by using a structured arra
ax=app.UIAxes;
ax.Children;
h1 = findall(ax, 'type', 'line'); % Line objects
nlines=numel(h1);
Assign the desired plot parameters to a struct "S"
for i=1:nlines
thisLine=h1(i);
S(i).Xdata=thisLine.XData; S(i).Ydata=thisLine.YData;
S(i).Colour=thisLine.Color;
S(i).LineStyle=thisLine.LineStyle;
S(i).LineWidth=thisLine.LineWidth;
S(i).DName=thisLine.DisplayName;
end
Save to a .MAT file
try
[file,folder]=uiputfile({'*.mat','Matlab Files'},'Save Data',app.startfolder);
catch
[file,folder]=uiputfile({'*.mat','Matlab Files'},'Save Data','C:\');
end
app.startfolder=folder;
savepath=fullfile(folder,file);
save(savepath,"-struct",'S')
But I keep getting this error:
Error using save
The argument to -STRUCT must be the name of a scalar structure variable.
I have checked the class of S and the fieldnames contained within it:
fields = fieldnames(S)
class(S)
fields =
6×1 cell array
{'Xdata' }
{'Ydata' }
{'Colour' }
{'LineStyle'}
{'LineWidth'}
{'DName' }
ans =
'struct'
Thanks for any help

请先登录，再回答此问题。

采纳的回答

Stephen23
Stephen23 2024-6-24
编辑：Stephen23 2024-6-24
Explanation: your structure is not scalar: it has nlines elements. The -struct option only works with scalar structures.
Error using save
The argument to -STRUCT must be the name of a scalar structure variable.
% ^^^^^^
Solutions:
  • either get rid of the -struct option, or
  • create a scalar structure (by making the fields arrays, not the structure).
Tip: always LOAD into an output variable!
  3 个评论
显示 1更早的评论
Steven Lord
Steven Lord 2024-6-24
Ran in:
Since several of the properties you're trying to store in the struct are non-scalar, it won't work as you wrote it. But you could have the fields of the scalar struct contain cell arrays, where each cell in the array can have data of different sizes depending on the properties of the specific line you're trying to store inside it.
h = plot(1:10, 1:10, 'r-', 1:7, 10:-1:4, 'k:');
for k = 1:numel(h)
S.XData{k} = h(k).XData;
S.YData{k} = h(k).YData;
end
disp(S)
XData: {[1 2 3 4 5 6 7 8 9 10] [1 2 3 4 5 6 7]} YData: {[1 2 3 4 5 6 7 8 9 10] [10 9 8 7 6 5 4]}
isscalar(S) % yes
ans = logical
1
isstruct(S) % also yes
ans = logical
1
cd(tempdir)
save('mydata.mat', '-struct', 'S')
whos -file mydata.mat
Name Size Bytes Class Attributes XData 1x2 344 cell YData 1x2 344 cell
P = load('mydata.mat')
P = struct with fields:
XData: {[1 2 3 4 5 6 7 8 9 10] [1 2 3 4 5 6 7]} YData: {[1 2 3 4 5 6 7 8 9 10] [10 9 8 7 6 5 4]}
isequal(P, S)
ans = logical
1

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Structures 的更多信息

标签

产品


版本

R2023b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by