fcell2csv - Fastest Cell Array to CSV-file

writes nD cell array into a ASCII delimited file (e.g., *.csv) using c-mex.

I've found a series of functions (`cell2csv`) that writes cell array content in to a *.csv file.

All of these functions is inefficient to handle a large cell array (number of nows > 20000), and none can handle a nD cell array.

So, I created this function fcell2csv that adopts c-mex file to improve performance.

`fcell2csv` is about 40~90 times faster than the codes found in FEX !

NOTE!

The c-mex file is necessary.

Run the following code to compile.

mex cell2csv_mex.c -R2018a -O

Run the following code for comparison.

 x = [{'This', 'is', 'a', 'cell', 'time', 'test.'}; num2cell([(1:50000)', rand(50000,5)])];
% Compare to built-in `writecell`/ `cell2csv`
tic; writecell(x, 'writecell.csv'); t1 = toc
tic; cell2csv('cell2csv.csv', x); t2 = toc % removing loop % https://www.mathworks.com/matlabcentral/fileexchange/73240-faster-cell-array-to-csv-file-more-improved-cell2csv-m
tic; cell2csv('cell2csv.csv', x); t3 = toc % https://www.mathworks.com/matlabcentral/fileexchange/47055-cell-array-to-csv-file-improved-cell2csv-m
tic; fcell2csv('fcell2csv.csv', x); t4 = toc % my c-mex

On my notebook (i7-8550u)

t1~33.127151 seconds

t2~8.365726 seconds

t3~11.168033 seconds

t4~0.513955 seconds

WIN!!