Hi all, I guess this boils down to a syntax question, or maybe a method question. Let's say I have read in data (mix of text and numbers) from an Excel file, into a cell array. Let's say this data array -- call it dataCell -- has 5 rows and 4 columns.
A script has determined that rows 1, 2, and 4 have something in common. I want to group them. Similarly, the script has determined that rows 3 and 5 have something in common, so I want to group those too. In this example, the result needs to be two groups. Next time, there might be 1 group, or 50, or any other number of groups. It is not a fixed number.
I want to create a cell array of cell matrices. Each sub-array is a cell matrix that contains a group of data rows that belong together. So in my example, my cell array will contain two sub-arrays. The first will be a 3x4 cell matrix. The second will be a 2x4 cell matrix. Easy enough, right?
A cell array called rowMatches lists the grouped rows. It would look like this for the example: rowMatches = {[1;2;4];[3;5]} Make sense?
Now, how do I write rows 1, 2 and 4 to my first sub-matrix, and rows 3 and 5 to my second? It would be slick if there were a notation kinda like this (even slicker if I could eliminate the for loop):
groupedDataCell={};
for i=1:length(rowMatches)
groupedDataCell=[groupedDataCell;{dataCell{rowmatches{i,:}}}]
end
I probably botched the number of { and }, but you get the idea. If such a thing is possible, how?
Barring that, it's for loops... right? If I start with
then I know how to loop through the data and append each data row to the appropriate sub array. In other words, if I can start with
, I am fine from there on.
But I can't. I won't know how many sub-array (here two, maybe more next time). I would have thought this would work (or about a million variants I've tried):
then loop as many time as needed...
groupedDataCell=[groupedDataCell;{}]
to get this {{};{}} (I don't really care if it is vertical or not)
but MATLAB doesn't think that way. The concatenate function returns {{}} with every iteration.
So, question. How do I create a cell array of n empty cell arrays, where n can vary?
Second question. I created the empty arrays to write data to. Is there another method that would shortcut the need for the empty array (which on its own is useless)?
Thanks all!
Aram
