indexing cell array of arrays

I have a cell array with M arrays of [Nx1] elements in each cell. How do I create a cell array with the same M arrays but with the first K elements of each cell?

Answer 1

[Evan]

cellfun(@(x)x(1:K),C,'uni',0) %Where C is your original cell array

[John Petersen]

Thanks!

[Evan]

No problem!

[Evan]

Note that, when using implicit functions with cellfun, operation will often be slower than a FOR LOOP would be (this is because cellfun has to do the looping anyway, plus some overhead). So, in cases where you're working with large arrays and/or operation time is quite important, my method above is not ideal.

Answer 2

[Azzi Abdelmalek]

for k=1:numel(A)
  A{k}=A{k}(1:4);
end

[Jan]

I still prefer this due to the speed.

[Evan]

Yes. I'll make a comment on my answer noting that Azzi's is preferred in all cases except where you want a quick and messy answer.

Answer 3

[Azzi Abdelmalek]

If A is your cell array

cellfun(@(x) x(1:k),A,'un',0)

Answer 4

[Daniel Shub]

It is not clear why you have a cell array with each element having Nx1 data, but if all the Nx1 arrays are the same type you can use CELL2MAT. Sticking with the one line answers:

mat2cell(subsref(cell2mat(x), struct('type', {'()'}, 'subs', {{1:K, ':'}})), K, ones(M, 1));

where x is your cell array.

If the M Nx1 arrays are different classes, for example from the output of

    data = textscan(fileID,'%s %s %d %f %f');

I would convert my cell array into a structure array with meaningful field names

 tempCellMat = cellfun(@(x)mat2cell(x, ones(length(x), 1), 1), data, 'UniformOutput', false);
 structArray = cell2struct([tempCellMat{:}], {'Name','dateStr','age','weight','height'}, 2);

You can then do structArray(1:k).

[John Petersen]

Why I have a cell array: I'm using textscan to read in a file with strings, integers and floats on each line. example:

data = textscan(fileID,'%s %s %d %f %f');

[Daniel Shub]

Ahh, so each of your M arrays of [Nx1] elements is of a potentially different class. This means you cannot use CELL2MAT and my answer will not work.... See my edit.