Efficient slicing of cell array?

I have a cell array of the form:

c =
  [1x100 double]
  [2x150 double]
  [3x200 double]

And I would like to create a 6x50 matrix consisting of all rows and the first 50 columns of each constituent matrix. Is there an efficient way to do this?

Answer 1

[Andrei Bobrov]

variant

cell2mat(cellfun(@(x)x(:,1:50),C,'un',0));

[EGTork]

Thanks, Andrei. For reference, I compared this cell array approach against directly indexing a matrix to create a submatrix. The cell array solution took about 5X as long, which is not bad considering the extra flexibility provided by cell arrays.

Specifically, I took a cell array containing five 10x100,000 matrices, and used your approach to generate a 50x75,000 submatrix. I compared this to directly indexing into a 50x100,000 matrix to create a 50x75,000 submatrix. For matrices of this size, there was a 5X penalty for using cell arrays instead of a matrix. For smaller matrices, the penalty was somewhat higher (~10X).