MATLAB Answers

Interleaving columns of two cell arrays

19 views (last 30 days)
Raphael Chazelle
Raphael Chazelle on 19 May 2016
Edited: the cyclist on 19 May 2016
Hey all,
I have two cell arrays:
  • ca = 7x9 cell array where each cell is a block of pixels 64x64x3
  • ca2 = 7x8 cell array where each cell is a block of pixels 64x64x3
I would like to interleave the cell array by columns like so:
  • ca3 = {ca{:,1};ca2{:,1};ca{:,2};ca2{:,2};ca{:,3};ca2{:,3};ca{:,4};ca2{:,4};ca{:,5};ca2{:,5};ca{:,6};ca2{:,6};ca{:,7};ca2{:,7};ca{:,8};ca2{:,8};ca{:,9}}';
I'm sure there has to be a more programmatic way of doing this and in a more extensible fashion(where if I have more then 8/9 columns I wouldn't have to keep adding to the code).
Thanks! Hope this makes sense

Accepted Answer

Kirby Fears
Kirby Fears on 19 May 2016
Edited: Kirby Fears on 19 May 2016
Here's a function I wrote for you. It contains a subfunction to create the interleaving index. Save this to interleaveCells.m and try calling it.
function c = interleaveCells(c1,c2)
% Make index for interleaving cells
ind = interleaveIndex(size(c1,2),size(c2,2));
% Combine cells
c = [c1, c2];
% Interleave cells
c = c(:,ind);
function ind = interleaveIndex(n1,n2)
ind = NaN(1, n1 + n2);
i = 1;
j = 1;
while i<=n1,
ind(i+j-1) = i;
i = i + 1;
if j<=n2,
ind(i+j-1) = n1 + j;
j = j + 1;
end
end
while j<=n2,
ind(i+j-1) = n1 + j;
j = j + 1;
end
Hope this helps.
  2 Comments
Kirby Fears
Kirby Fears on 19 May 2016
Great. I am editing in a change that simplifies the subfunction as well.
Cheers.

Sign in to comment.

More Answers (2)

the cyclist
the cyclist on 19 May 2016
I think this does what you want
% Your actual data here. (These are empty, but wouldn't be for your application)
ca = cell(7,9);
ca2 = cell(7,8);
% Append extra, empty column of cells, so that we can concatenate below
ca2_tmp = [ca2, cell(7,1)];
% Concatenate top-to-bottom, then reshape
ca3 = reshape([ca;ca2_tmp],7,18);
% Trim spurious final column
ca3(:,end) = [];
  1 Comment
Raphael Chazelle
Raphael Chazelle on 19 May 2016
This one works! the one below is close but not the desired output!

Sign in to comment.


the cyclist
the cyclist on 19 May 2016
Edited: the cyclist on 19 May 2016
ca3 = [ca,ca2];
idx = reshape(1:18,[],2)'
ca3 = ca3(:,idx(1:end-1));
EDIT: Fixed this to get the indexing right. Arguably a bit easier than my other solution, but basically works on the same principle.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!