Adding column in cell array before converting to a matrix.

I have a cell array with 23 X 1 doubles. Within each cell double there are two columns with thousands of rows.

Each of the 23 cells is representative of a sample in a project.

I need to convert this cell array into a matrix with all the data, but the final matrix needs to have an identifer with the cell name from the previous array (ex. 1,2,etc). The screenshot is an example of what I'm looking for within the first cell of the array. How do I add a column with values to one cell in a cell array?

Answer 1

[Stephen23]

Here are a couple of approaches. First lets create some fake data:

C = {randi(9,3,2),randi(9,2,2),randi(9,4,2)}

C = 1x3 cell array
    {3x2 double}    {2x2 double}    {4x2 double}

C{:}

ans = 3x2

8 2 5 1 3 1

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ans = 2x2

7 8 1 2

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ans = 4x2

1 6 5 3 8 3 8 2

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Method one: CELLFUN and REPELEM:

X = cellfun(@height,C);
Y = 1:numel(X);
D = [vertcat(C{:}),repelem(Y(:),X,1)]

D = 9x3

8 2 1 5 1 1 3 1 1 7 8 2 1 2 2 1 6 3 5 3 3 8 3 3 8 2 3

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Method two: FOR-loop (modifies the original data):

for k = 1:numel(C)
    C{k}(:,3) = k;
end
M = vertcat(C{:})

M = 9x3

8 2 1 5 1 1 3 1 1 7 8 2 1 2 2 1 6 3 5 3 3 8 3 3 8 2 3

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https://www.mathworks.com/matlabcentral/discussions/tips/847976-tutorial-comma-separated-lists-and-how-to-use-them

[Emily]

This worked! Thank you very much.

[Stephen23]

@Emily: please remember to click the accept button if my answer helped you!