Change string of text into multiple lines

I have a string of text that needs to be formatted and saved as a txt file. The string is in this format:

,1,1880802442166,1,751702411341,1,751702411358,1,751702411365,1,751702411372,1,751702411389,1,751702459060,1,751702459077,1,751702459084,3,751702459091,1,751702459107,1,751702459114,2,751702459121,1,751702459145...

It needs to be output in this format:

,1,1880802442166

,1,751702411341

,1,751702411358

,1,751702411365

,1,751702411372

,1,751702411389

,1,751702459060

,1,751702459077

,1,751702459084

,3,751702459091

,1,751702459107

,1,751702459114

,2,751702459121

,1,751702459145...

It's for an inventory list that was recorded in the wrong format.

Thanks in advance,

Nick

Answer 1

[Azzi Abdelmalek]

s=',1,1880802442166,1,751702411341,1,751702411358,1,751702411365,1,751702411372,1,751702411389,1,751702459060,1,751702459077,1,751702459084,3,751702459091,1,751702459107,1,751702459114,2,751702459121,1,751702459145'
a=regexp(s,',','split')
a(1)=[]
b=reshape(a,2,[])'
c=cellfun(@(x,y)  [',' x  ','  y], b(:,1),b(:,2),'un',0)
fid=fopen('file.txt','w')
for k=1:numel(c)
  fprintf(fid,'%s \r\n',c{k,:})
end
fclose(fid)

[Nicholas]

I needed a blank line between each in value in the list, but I just added an extra

\r\n

in

fprintf(fid,'%s \r\n',c{k,:})

Thanks

Answer 2

[Andrei Bobrov]

s = ',1,1880802442166,1,751702411341,1,751702411358,1,751702411365,1,751702411372,1,751702411389,1,751702459060,1,751702459077,1,751702459084,3,751702459091,1,751702459107,1,751702459114,2,751702459121,1,751702459145';

out = mat2cell(s,1,diff([regexp(s,',\d,'),numel(s)+1]))