# Exrapolate values from cell matrix and operations with cell elements

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EldaEbrithil on 14 Oct 2020
Commented: Ameer Hamza on 15 Oct 2020
Hi all
i have a cell matrix where each cell is nx3 double. Assuming you have the coordinates ( [y k] where y and k are arrays )of the cells that interest me, I want, from these selected cells, to extrapolate only the first of the three columns.
How can be done?
Thank you for the help
Regards

Ameer Hamza on 14 Oct 2020
Edited: Ameer Hamza on 14 Oct 2020
I am not sure about the point related to extrapolation. If you just want to extract the first column of selected cells, then you can try this
C; % cell matrix
y; % row index of selected cells
k; % column index of selected cells
idx = sub2idx(size(C), y, k);
C_selected = C(idx);
first_columns = cellfun(@(x) {x(:,1)}, C_selected);
if all columns have same length then you can create a matrix
first_columns = [first_columns{:}];
Ameer Hamza on 15 Oct 2020
It depends on what you are trying to do. / is used for "matrix division", whereas ./ is used for element-wise division. If corresponding cells of A and B have an equal number of elements, then I think you want to use
C{i}=A{i}./{B{i}