Creating a table from different sized vectors

251 views (last 30 days)
I have a number of vectors (x1,y1,x2,y2, etc) with different lengts and I want to extract them to a .csv containing all these. Specifically,
  • 1st column = x1 (289 rows)
  • 2nd column = y1 (289 rows)
  • 3rd column = x2 (300 rows)
  • 4th column = y2 (300 rows)
I try to use the horzcat but it does not work due to different size. Any ideas or solutions?
  1 Comment
Stephen23 on 17 Dec 2015
Rather than storing these in numbered variables these vectors should really be stored in a cell array. Then the task becomes a trivial loop with indexing to allocate the vectors into a proallcoated array.
Numbered variables are invariably a bad idea:

Sign in to comment.

Accepted Answer

Renato Agurto
Renato Agurto on 17 Dec 2015
Hi, you could try:
A = nan(no_of_columns, longest_array); % or zeros or whatever you want to fill the unused spaces
and then (or for example in a for loop):
A(1:length(x1),1) = x1;
A(1:length(y1),2) = y1;
I hope this is what you want
  1 Comment
ju.shu on 17 Jun 2020
what if I have two columns each one of them 2xn (like 2x4012, and 2x9877) fo instance the columns represent points coordinates, how can I save the 2 columns in a table??

Sign in to comment.

More Answers (3)

the cyclist
the cyclist on 17 Dec 2015
Depends on what you want to appear in the "empty" spot. You could use NaN. Then
M = [[x1; nan], [y1; nan], x2, y2]
and then export the matrix M.

the cyclist
the cyclist on 17 Dec 2015
One possibility is to store them in a cell array first, in which case empty will be empty.
M = cell(300,4);
M(1:299,1) = num2cell(x1);
M(1:299,2) = num2cell(y1);
M(:,3) = num2cell(x2);
M(:,4) = num2cell(y2);

Image Analyst
Image Analyst on 17 Dec 2015
I'd just use fprintf() and write it out manually.

Community Treasure Hunt

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

Start Hunting!