Creating new field names within a new structure when trying to reshape data

Question

pkll201 2023-9-15

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2021476-creating-new-field-names-within-a-new-structure-when-trying-to-reshape-data

评论： Matt J 2023-9-15

I have a dataset saved into a structure which each person has several trials of 360 data points. The data is structured as variable1.pptID.data_CW. Where each person is a new field of pptID, and each person's data is split into two groups of trials (data_CW and data_CCW) where there are several trials in each group. For example:

variable1.pt15.dataCCW = transpose([1:360; 1:360; 1:360; 1:360; 1:360]);
variable1.pt15.dataCW = transpose([1:2:720; 1:2:720; 1:2:720; 1:2:720; 1:2:720]);
variable1.pt16.dataCCW = transpose([1:360; 1:360; 1:360; 1:360; 1:360; 1:360; 1:360; 1:360]);
variable1.pt16.dataCW = transpose([1:2:720; 1:2:720; 1:2:720; 1:2:720; 1:2:720; 1:2:720; 1:2:720; 1:2:720]);

I am trying to reshape each trial into 72 sections of 5 data points. If I was to do this for each column separately, I could run this as:

reshape((variable1.pt15.dataCCW(:,1)), 5, []);

However, I am trying to get this so I don't have to run it for every trial as this would be pretty inefficient! I have tried to run it within a for loop as follows:

pptID = ('pt15');
var1CCW = variable1.(pptID).data_CCW;
var1CW = variable1.(pptID).data_CW;
[m,n]=size(var1CCW);
for c_loop=1:n %do separately for each time series (i.e. each participant or each trial)
    splitCCW(:,c_loop)= reshape((var1CCW(:,c_loop)), 5, []);
    splitCW(:,c_loop)= reshape((var1CW(:,c_loop)), 5, []);
end

However, I found that as the reshape is a different size to the initial grouping of trials I realised I would have to make each trial into a separate field of a structure. I then tried the following:

pptID = ('pt15');
var1CCW = variable1.(pptID).data_CCW;
var1CW = variable1.(pptID).data_CW;
[m,n]=size(var1CCW);
for c_loop=1:n %do separately for each time series (i.e. each participant or each trial)
    splitCCW.(pptID).a({c_loop})= reshape((var1CCW(:,c_loop)), 5, []);
    splitCW.(pptID).a({c_loop})= reshape((var1CW(:,c_loop)), 5, []);
end

However, this still does not seem to work. I think my naming of the new fields of the structure is incorrect - but I can't figure out the right way of doing this! It keeps coming up with the following error message:

Unable to use a value of type cell as an index.

Any thoughts about why this might be would be appreciated, as well as ways to further improve my code. I may just be going about it in the complete wrong way! Please let me know if anything requires further clarification

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Matt J 2023-9-15

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2021476-creating-new-field-names-within-a-new-structure-when-trying-to-reshape-data#answer_1311301

编辑：Matt J 2023-9-15

在 MATLAB Online 中打开

Your post is hard to follow, so I'm doing a bit of guessing as to what you want. Regardless, I think the data organization strategy needs some reconsidering, both before and after the reshaping.

I think first of all that your initial data should be organized as a struct array pt, where pt(i) is one person:

pt(1).CW=rand(360,4);
pt(1).CCW=rand(360,4);
...
pt(16).CW=rand(360,7);
pt(16).CCW=rand(360,7);

Also, I don't think you should be splitting up the trial data into separate fields or cells. Each matrix of trial data can be reshaped to a 3D array that is 5x72xN quite easily:.

for i=1:numel(pt)
    
    pt(i)=structfun(@(z)reshape(z,5,72,[])   , pt(i), 'uni',0);
    
end

7 个评论
显示 5更早的评论隐藏 5更早的评论

pkll201 2023-9-15

Oh that's great, thank you so much!! That works perfectly. Thank you for all your help - you've come from a perspective I would have never thought of on my own :)