Creating a struct with means and standard deviations

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BA 2022-9-16

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评论： BA 2022-9-16

采纳的回答： Chris

Event_1_2.xlsx

I'd like to create a script that loops through multiple subjects and creates a new structure with doubles in it.

First Column of Master Table: I want the SubjectID but I only want it once, I don't want it repeating like it is in the dataset I've attached.

Second Column of Master Table: I want it to lead to a struct with the means of each of the six events. So in the new struct, I want the first column of the first row to be for event 1_a, second column first row event 2_a, etc.

Third Column of Master Table: I want it to lead to a struct with the standard deviation of each of the six events.

Here's an example of what I want it to look like:

The examples of mean and standard deviation doubles are only for one subject. I'd like to loop this for every subject in the data table to create a master struct.

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采纳的回答

Chris 2022-9-16

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编辑：Chris 2022-9-16

It looks like you want an array of structs. Use strings or uint64 for the IDs

S = struct('id',uint64(123456),'mean',rand(3),'stdev',rand(1,3))
S = struct with fields:
       id: 123456
     mean: [3×3 double]
    stdev: [0.7411 0.1904 0.5026]
% Add new data
for idx = 2:4
    S(idx).mean = rand(3);
    S(idx).stdev = rand(1,3);
    S(idx).id = uint64(randi(1e9));
end
S
S = 1×4 struct array with fields:
    id
    mean
    stdev
% Retrieve data
x = S(3).stdev
x = 1×3
    0.6080    0.0728    0.3028
y = [S(1:2).id]
y = 1×2
      123456   614065544

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Chris 2022-9-16

编辑：Chris 2022-9-16

Unstack sounds useful, but I'm unfamiliar with it and man, I need to learn some table stuff.

@BA How about something like this?

EventData = readtable('Event_1_2.xlsx');
vars = T.Properties.VariableNames;
[u,~,ic] = unique(EventData.UserID);
for idx = 1:numel(u)
    Updating(idx).ID = u(idx);
    T = EventData(ic==idx,2:end);
    Updating(idx).stdev = array2table(std(T{:,:}),'VariableNames',vars);
    Updating(idx).mean = array2table(mean(T{:,:}),'VariableNames',vars);
end