MATLAB: How to combine arrays in a cell from 71 x 12 to 1 x 71

cell arraysMATLAB

Dear all,

I had a cell named C which was 1 x 71 cell. I use the code below to split it into Cmo that is 71 x 12 cell array:

Cmo = cell(numel(C),12);  
for i = 1:numel(C)
    Cmo(i,:) = arrayfun(@(m){C{i}(month(C{i}.date) == m, :)},1:12);
end

I have done what I needed with split cell (Cmo) and I want to roll back it in 1 x 71 cell array again, and that is my problem.

Here is my code for doing that so far, But unfortunately it doesn't work and at the end, the Cnew will be a 71 x 1 cell (instead of 1 x 71 and field with blank cells).

% Cmo is 71 x 12 cell, and Cnew is output (1 x 71) cell
Num = ceil(length(Cmo)/12)*12-length(Cmo);
Cnew = [Cnew,cell(1,Num)]
Cnew = cell(1,72);
Cnew = reshape(Cnew,12,length(Cnew)/12);
Cnew = reshape(Cnew,size(Cnew,2)*12,1);

I don't know what to do, so if anyone knows what should I do I would be so grateful. I attached both C (the first version of Cmo) and Cmo.

Thank you all for all your helps answers and comments.

Best Regards

Best Answer

% Loop through the rows of Cmo and combine them 
% back into 1 table.  Then sort the rows so that
% they are in chronological order ("date" column).
Cnew = cell(1,size(Cmo,1));
for i = 1:size(Cmo,1)
    Cnew{i} = sortrows(vertcat(Cmo{i,:}),'date');
end

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MATLAB: Run this code for every certain columns of tables in a cell and saving the result in new cell

Hello, I have taken a look at your workspace variable ("C"), and i think you should consider writing that program as a function file, so that you can use it for all tables in the cell array. You can use the code below and save it as your function file in the working (current) folder.

function SI = myfunction(Cn,rnum,colnum,tcol) % save this as a functionfile with filename: "myfunction.m"
%Summary of "myfunction"
% SI = output
% Cn = Cell array storing all tables
% rnum = row index of table in cell array
% colnum = column index of table in cell array
% tcol = column number of table variable ("rrr24") on which you are doing the computations
td = table2array(Cn{rnum, colnum}(:,tcol)); % example for C{1, 1}
n=numel(td);
sc_set= [3,6,12,24]; 
SI=zeros(n,length(sc_set)); 
for q = 1:length(sc_set)
  sc = sc_set(q); % I have replaced "k" with "q" on this line
  if numel(td(td>=0))/numel(td)~=1
      SI(n,q)=nan;
  else
      SI(1:sc-1,q)=nan;
      A1=[];
      for i=1:sc
          A1=[A1,td(i:numel(td)-sc+i)]; %#ok<AGROW>
      end
      Y=sum(A1,2);
      nn=numel(Y);
      SI1=zeros(nn,1);
      for k=1:12
          d=Y(k:12:nn);
          nnn=numel(d);
          bp=zeros(nnn,1);
          for i=1:nnn
              bp(i,1)=sum(d(:,1)<=d(i,1));
          end
          y=(bp-0.44)./(nnn+0.12);
          SI1(k:12:nn,1)=y;
      end
      SI1(:,1)=norminv(SI1(:,1));
      %output
      SI(sc:end,q)=SI1;
  end
end
end

After that, consider using the code below. It should do nicely:

Cnew=cell(1,size(C,2)); % pre-allocating your new array
for r=1:size(C,1)
    for m=1:size(C,2)
        SI{r,m}= myfunction(C,r,m,11);% On this line, "11" is the column index of "rrr24" (your table variable)
        Cnew{r,m}=cell2table(C{r,m}.station_name); % input names under the "station_name" variable of your old tables into the new cell array based on their indexed locations
        Cnew{r,m}.Output=SI{r,m}; % Add column variable, "Output" holding computed values to each table in the new cell array based on their indexed positions
        Cnew{r,m}.Properties.VariableNames{1}='Station Name'; % variable name for first column of each table
    end
end

MATLAB: Help preallocating variables for a table

C is a matrix with doubles in it

In that case,

function caTable = makeCaTable(caCM)
   %doc goes here
   %  caCM: a 2D(?) cell array
   %  caTable:a table with 4 variables: Frame, PosX, PosY, NumberOfCells
 
   chopped = cellfun(@(x) chop(x, 0), caCM(1, :), 'UniformOutput', false)';  %transpose for easier repelem and cell2mat
   NumberOfCells = cellfun(@(m) size(m, 1), chopped);
   NumberOfCells = repelem(NumberOfCells , NumberOfCells );
   Frame = repelem((1:size(chopped, 1))', NumberOfCells);
   chopped = cell2mat(chopped);
   PosX = chopped(:, 1);
   PosY = chopped(:, 2);
   caTable = table(Frame, PosX, posY, NumberOfCells);
end

As a rule you shouldn't be using cell arrays unless you need to, they're slower to process and takes a lot more memory than a matrix (15 times more if each cell is just a scalar double).

Note that I'm replicating the number of cells for all rows of a frame instead of having '-' for all rows but the first of the frame. It's rarely a good idea to mix numbers and characters in a variable. If you want a different value for all but the first row, I'd recommend using NaN instead. It's trivially done:

     NumberOfCells = repelem(NumberOfCells, NumberOfCells);  %continuing on from there
     NumberOfCells([false; diff(NumberOfCells) == 0]) = NaN;

If you really want a '-', then it's slightly more complicated:

     ncells = repelem(NumberOfCells, NumberOfCells);  
     NumberOfCells = num2cell(ncells);
     NumberOfCells([false; diff(NumberOfCells) == 0]) = {'-'};

Best Answer

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MATLAB: Run this code for every certain columns of tables in a cell and saving the result in new cell

MATLAB: Help preallocating variables for a table

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