Extract first and last row of each subarray in a cell array
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Hello, if I have a 7×1 cell array, how could I extract the first and last row of each sub-array.
So if my cell looks like this:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1350544/image.png)
I would like to end up with a matrix that looks like this (I put spaces so it is more clear what I want from each sub-array) :
50.0000 30.0000
50.4897 31.9177
61.0370 51.2245
61.5267 53.1422
61.5267 65.1422
60.6073 66.8252
58.5037 67.4803
54.2273 68.6080
52.1029 69.2125
51.0000 71.0000
I included the 7x1 cell array file.
Thanks.
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Paul
2023-4-10
编辑:Paul
2023-4-10
I think this works even if the first and last row of a cell are identical.
load(websave('cellArray.mat','https://www.mathworks.com/matlabcentral/answers/uploaded_files/1350539/cellArray.mat'));
out = cellfun(@(x) x(1:max(end-1,1):end,:),group1,'UniformOutput',false)
out = vertcat(out{:})
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Walter Roberson
2023-4-10
By the way, @Paul the websave() work-around is no longer generally needed. If you use the attachment toolbar icon, then the second tab, "Link from this thread" allows you to select items that other people have attached in the Question, a makes them available for the Run facility (without duplicating them -- it makes links internally.)
更多回答(2 个)
Walter Roberson
2023-4-10
output = cellfun(@(C) C(unique([1, end]), :), YourCellArray, 'uniform', 0)
The unique() is there to prevent it from accidentally copying data when there happens to be only one row in a cell
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the cyclist
2023-4-10
I believe this does what you want.
load cellArray.mat
c = cellfun(@(x)unique(x([1 end],:),"row"),group1,"UniformOutput",false);
m = cell2mat(c)
The cells that have one row make this a bit tricky. The first and last row of a one-row are the same, but it looks like you don't want it listed twice. So, I use "unique" to get only one of them. But, this algorithm will fail if the first and last row of a multi-row array are identical.
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