Convert .csv to .out (complex numbers) - matlab

Question

I have a csv file that has complex numbers.
This is sample of some numbers I have in the csv file:
(0.12825663763789857+0.20327998150393212j),(0.21890748607218197+0.160563964013564j),(0.28205414129281525+0.09884068776334366j),(0.030927026479380615+0.26334550583848626j)
I want to read this file and then save in (.out) file all the real parts in the first column and all the imaginary parts in the second column (without the imaginary letter j).

Answer 1

Here is one attempt. It is slightly more complicated due to the ( and ) that surround your numbers.
First, use textscan to read the file. Since I guess you don't know how many numers are in the file, read everything into a singe string. Will work with mutiple lines, too:
filename = 'data.csv';
fid = fopen(filename);
content = textscan(fid, '%s');
fclose(fid);
For this purpose, content now is a slightly weird cell array (look at the textscan-docs for details). Just initialize the variable nums which will store the numbers and loop through content (if you know a bit more about your csv file, you might pre-allocate nums):
nums = [];
for c1 = 1:numel(content{1})
Next, split the string at every occurence of ,:
string_list = strsplit(content{1}{c1},',');
This gives another cell array. Loop through it to convert the strings to numbers (and end the outer loop):
for c2 = 1 : numel(string_list)
nums(end+1) = str2num(string_list{c2});
end
end
Last, just store the real and the imaginary part of the numbers in separate columns:
out = [];
out(:,1) = real(nums);
out(:,2) = imag(nums);
and save it to data.out.
Update As you mentioned precision, you could use
dlmwrite('data.out', out, 'precision','%.20f');
However, here you need to understand the floating point representation in Matlab. In particular, try to understand the following:
>> a = 0.12825663763789857
a =
0.1283
>> fprintf('%.20f\n', a)
0.12825663763789857397
>> eps(a)
ans =
2.7756e-17
Note that one could have done this without cenverting the strings to numbers, but the way above would allow you to use the data in Matlab instead of just saving it.

Answer 2

HEre is an attempt without converting your strings to numbers, therefore one does not have to deal with precision. It works with negative real and imaginary numbers, too. + signs are removed when written to the new file, - signs are preserved:
filename = 'data.csv';
fid = fopen(filename);
content = textscan(fid, '%s');
fclose(fid);
fid = fopen('data.out','w');
pattern = '(?<real>-{0,1}\d+.\d+)(?<imag>[+-]\d+.\d+)j';
for c1 = 1:numel(content{1})
result = regexp(content{1}{c1}, pattern, 'names');
for c2 = 1:numel(result)
fprintf(fid, '%s,%s\n', strrep(result(c2).real,'+',''), strrep(result(c2).imag,'+',''));
end
end
fclose(fid);