I'm trying to export data to a csv file. It should contain a header (from datastack) and restacked arrays with my data (from datastack). One line in datastack has the same length as dataset. The code below works but it removes parts of the first line from datastack. Any ideas why that could be? s = ','.join(itertools.chain(dataset)) + '\n' newfile = 'export.csv' f = open(newfile,'w') f.write(s) numpy.savetxt(newfile, (numpy.transpose(datastack)), delimiter=', ') f.close()