i trying use savreaderwriter library python. have dataframe read in via df = pd.read_csv . using following piece of code won't seem write rows file. with savreaderwriter.savwriter(savfilename, *args) writer: writer.writerows(df) i getting following error typeerror: 'str' object not support item assignment.any appreciated. this sample on https://pythonhosted.org/savreaderwriter/ savfilename = 'somefile.sav' records = [[b'test1', 1, 1], [b'test2', 2, 1]] varnames = ['var1', 'v2', 'v3'] vartypes = {'var1': 5, 'v2': 0, 'v3': 0} savreaderwriter.savwriter(savfilename, varnames, vartypes) writer: record in records: writer.writerow(record) i think can divide dataframe 3 fields(records, varnames, vartypes) way, can use method in pandas write data file. import pandas pd sensor_values = pd.dataframe([[1,'aaa','bbb'],[2,'ppp','xxx']], columns=[