acessing cell arrays with different number of rows

Hi,

I have cell array "out" 1x123 cells. Within each cell of out{1,1}, <1x3 cells. How can I access 2 and 3 columns of each cell within "out" and store in flows2 matrix. I am having a difficulty because each cell of "out" has different number of rows.

So, I tried this way

for j=1:length(csvFiles)
    formatOut = 'yyyy';
    flows2(:,j)=[str2num(datestr(datenum([out{1,j}{1,2}],1900),formatOut)) [out{1,j}{1,3}]];
end

I am receiving this error. Subscripted assignment dimension mismatch.

My question is, any other efficient way of doing this?

Any suggestion is appreciated.

Thanks in advance,

Answer 1

[Star Strider]

The only option I can see is to create flows2 as a cell array:

flows2{j} = ...

[Damith]

Now, next question is how can I access each cell of flows2 2nd column?

for example to acess the cell 1 of flows2 and 2nd column of cell 1.

flows2{1,1},2 or?

[Star Strider]

To get the contents of flows2{1}, use the curly-bracket notation:

% Create data: 
for j = 1:4
    flows2{j} = [randi(10,j+2,1)+2000  randi(10,j+2,1)];
end
% Getting the contents of ‘flows2{1}’: 
q = flows2{1}

produces:

q =

       2009     9
       2010     4
       2008     8

The ‘q’ variable here is now a (3x2) double array you can address as you would any other double array. (You cannot use cell2mat for flows2 because it has uneven columns.)

[Damith]

I understand. But is there a way to read the columns of each cell.? for example column 2 of each cell 1 and store is separate array.

[Star Strider]

I apologise for the misunderstanding.

To get the second column of flows2{1}:

q1 = flows2{1}
q2 = flows2{1}(:,2)

Here, ‘q1’ is the previous ‘q’ (to check the result), and ‘q2’ is the second column of flows2{1}.

[Damith]

Thanks. How can I store q2 values in different columns for all the cells. Something like this,

for i=1:length(csvFiles) 
    q2(:,i)=flows2{i}(:,2)
end

When I tried this I received this error: Subscripted assignment dimension mismatch.

I know know this is due to uneven number of rows of 2nd column of each cells. Is there a way to store with different names like q1,q2,....length(csvFiles)?

[Star Strider]

For the same reason as with flows2 (different size columns), you will need to store them in a cell array:

for i=1:length(csvFiles) 
    q2{i}=flows2{i}(:,2)
end

If you wanted to, you could do that in your ‘j’ loop. Simply add it as a separate line and save an extra loop.