How do I cut the columns in a cell of a cell array according to values in a numerical array?

Hi,

I have the following problem at hand:

I have a cell array called alldata with 24 cells. The first column in each cell of alldata contains seconds as single numbers. The second column contains measurment points.

I am trying to loop through all cells in alldata and shorten the columns in each cell at the beginning and at the end a little (by deleting the first few and the last few rows) (but not for every column).

To do this, I also have a numerical array called beginning_end with 24 rows relating to each of the 24 cells in alldata. The first column in beginning_end contains cut-off points (seconds in numbers) where I want to delete the first few seconds of a column in a cell and the second column in beginning_end contains cut-off points where I want to delete the last few seconds of a column in a cell.

If there is a NaN then I dont need to cut anything (from the beginning or end of a column).

To do this I would need to (find and) match the seconds in the rows of beginning_end with the seconds in the rows of the cells of alldata to get the row numbers and know where to cut correct?

How would such code look?

(I hope this is coherent enough to understand)

Thanks!

Answer 1

[Fifteen12]

I've made this a little long in order to improve legibility. Hope this works!

% Make sample data
foo = zeros(100, 2);
bar = zeros(100, 2);
for i = 2:100
    foo(i, 1) = foo(i-1) + rand;
    bar(i, 1) = bar(i-1) + rand;
    foo(i, 2) = i;
    bar(i, 2) = i;
end
alldata = {foo, bar};
beginning_end = [5.2, 20.1; 2.0, 25.5];

% Iterate through and filter
for i = 1:length(alldata)
    above_min = alldata{i}(:, 1) > beginning_end(i, 1);
    below_max = alldata{i}(:, 1) < beginning_end(i, 2);
    valid_rows = above_min & below_max;
    to_keep = alldata{i}([valid_rows, valid_rows]);
    to_keep = reshape(to_keep, [height(to_keep)/2, 2]); %Reshape from logical output
    alldata{i} = to_keep;
end

% Check that the data was filtered (this is just for error checking)
for i = 1:length(alldata)
    disp(sprintf('Data array %d, Height=%d', i, height(alldata{i})))
    disp(alldata{i}(1:2, :))
    disp(sprintf('\t  ...'))
    disp(alldata{i}(end-1:end, :))
end

Data array 1, Height=28

    5.4575    9.0000
    5.9736   10.0000

	  ...

   19.1717   35.0000
   19.8663   36.0000

Data array 2, Height=48

    2.5396    6.0000
    3.2197    7.0000

	  ...

   25.0505   52.0000
   25.2473   53.0000

[lil brain]

Hi @John Morris thanks!

However, when I run this I get the error:

Error in CRM_analysis (line 34)

above_min = alldata{i}(:, 1) > beginning_end(i, 1);

Undefined function 'gt' for input arguments of type 'cell'.

Error in CRM_analysis (line 34)

above_min = alldata{i}(:, 1) > beginning_end(i, 1);

Any idea why?

[lil brain]

Hi @John Morris nevermind I think it was because the cells had cells in them rather than numerical arrays.

[Fifteen12]

Great, hope you were able to get it to work!