merge multiple csv or xls files with different row and columns

Question

Massimo 2023-5-25

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https://ww2.mathworks.cn/matlabcentral/answers/1973639-merge-multiple-csv-or-xls-files-with-different-row-and-columns

评论： Walter Roberson 2023-5-26

Hello guys, i need help to do what describe in title. I have multiple csv files, with different rows and columns and i need to merge them in one single csv file. I don't know at all what to do.

I have created csv files, but if you think it's better dealing with xls files, i can also create them as xls.

However, whatever type they are, at the end i need to have just one single file (csv or xls).

Thanks

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Stephen23 2023-5-26

Isn't this something that WRITEMATRIX/WRITECELL/etal's RANGE option should be able to handle?

Walter Roberson 2023-5-26

@Stephen23

Not when you are writing to a csv file. To add columns to a csv file, the (internal) code would have to read the entire file, insert the new values, and write out the result. As opposed to xls files which can be updated in-place.

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Answer 1

Walter Roberson 2023-5-25

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https://ww2.mathworks.cn/matlabcentral/answers/1973639-merge-multiple-csv-or-xls-files-with-different-row-and-columns#answer_1244829

在 MATLAB Online 中打开

readcell() each file. Carefully concatenate them together

newrows = size(NewCell,1); newcols = size(NewCell,2);
AllCell(1:newrows, end:end+newcols) = NewCell;

afterwards writecell(AllCell)

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dpb 2023-5-26

在 MATLAB Online 中打开

% simulate some data returned from readcell
c{1}=num2cell(rand(4,3));
c{2}=num2cell(rand(1));
c{3}=num2cell(rand(3,2))
c = 1×3 cell array
    {4×3 cell}    {1×1 cell}    {3×2 cell}
A={};
for i=1:3
  [nr,nc]=size(c{i});       % readcell returns a nxm cell array
  A(1:nr,end+1:end+nc)=c{:}
end
A = 4×3 cell array
    {[0.3191]}    {[0.0762]}    {[0.4635]}
    {[0.0297]}    {[0.7799]}    {[0.7663]}
    {[0.7568]}    {[0.2999]}    {[0.0310]}
    {[0.9638]}    {[0.1558]}    {[0.1982]}
Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 4-by-3.

The output cell array still has to be rectangular even though it is a cell array; you could only catenate the disparate cell arrays by augmenting the sizes to all have the same number of rows -- if the first is the tallest, then you can do it by adding to the next one read; if one of those has more rows than a prior one, then have to augment the accumulator array to its size.

You could encapsulate the returned cell arrays from readcell into a cell array as I did to create the sample data, but when you do that, writecell doesn't write each cell in turn after catenating, it will just expand them all in a row...

dpb 2023-5-26

在 MATLAB Online 中打开

% simulate some data returned from readcell
c{1}=num2cell(rand(4,3));
c{2}=num2cell(rand(1));
c{3}=num2cell(rand(3,2))
c = 1×3 cell array
    {4×3 cell}    {1×1 cell}    {3×2 cell}

Assume we catenate the return from readcell as above

writecell(c, "Combined.csv")  % write it out
Error using writecell
Nested cell arrays are not supported.

I don't see any magic elixir here that would work without more effort. One could write a spreadsheet file by writing each file separately to the next available columns with the 'range' argument, but would have to keep running total of number columns written already.

It still doesn't make much sense to me to put such data together this way...

Walter Roberson 2023-5-26

在 MATLAB Online 中打开

% simulate some data returned from readcell
c{1}=num2cell(rand(4,3));
c{2}=num2cell(rand(1));
c{3}=num2cell(rand(3,2))
c = 1×3 cell array
    {4×3 cell}    {1×1 cell}    {3×2 cell}
A={};
for i=1:3
  [nr,nc]=size(c{i});       % readcell returns a nxm cell array
  A(1:nr,end+1:end+nc)=c{i}
end
A = 4×3 cell array
    {[0.7031]}    {[0.1522]}    {[0.8339]}
    {[0.0438]}    {[0.9413]}    {[0.5937]}
    {[0.2233]}    {[0.5167]}    {[0.3666]}
    {[0.9291]}    {[0.7885]}    {[0.6691]}
A = 4×4 cell array
    {[0.7031]}    {[0.1522]}    {[0.8339]}    {[  0.3683]}
    {[0.0438]}    {[0.9413]}    {[0.5937]}    {0×0 double}
    {[0.2233]}    {[0.5167]}    {[0.3666]}    {0×0 double}
    {[0.9291]}    {[0.7885]}    {[0.6691]}    {0×0 double}
A = 4×6 cell array
    {[0.7031]}    {[0.1522]}    {[0.8339]}    {[  0.3683]}    {[  0.1050]}    {[  0.4291]}
    {[0.0438]}    {[0.9413]}    {[0.5937]}    {0×0 double}    {[  0.4317]}    {[  0.6401]}
    {[0.2233]}    {[0.5167]}    {[0.3666]}    {0×0 double}    {[  0.4467]}    {[  0.6084]}
    {[0.9291]}    {[0.7885]}    {[0.6691]}    {0×0 double}    {0×0 double}    {0×0 double}