如何分割csv文件和条件？

Question

我有这个csv文件：

89,Network activity,ip-dst,80.179.42.44,,1,20160929
89,Payload delivery,md5,4ad2924ced722ab65ff978f83a40448e,,1,20160929
89,Network activity,domain,alkamaihd.net,,1,20160929
90,Payload delivery,md5,197c018922237828683783654d3c632a,,1,20160929
90,Network activity,domain,dnsrecordsolver.tk,,1,20160929
90,Network activity,ip-dst,178.33.94.47,,1,20160929
90,Payload delivery,filename,Airline.xls,,1,20160929
91,Payload delivery,md5,23a9bbf8d64ae893db17777bedccdc05,,1,20160929
91,Payload delivery,md5,07e47f06c5ed05a062e674f8d11b01d8,,1,20160929
91,Payload delivery,md5,bd75af219f417413a4e0fae8cd89febd,,1,20160929
91,Payload delivery,md5,9f4023f2aefc8c4c261bfdd4bd911952,,1,20160929
91,Network activity,domain,mailsinfo.net,,1,20160929
91,Payload delivery,md5,1e4653631feebf507faeb9406664792f,,1,20160929
92,Payload delivery,md5,6fa869f17b703a1282b8f386d0d87bd4,,1,20160929
92,Payload delivery,md5,24befa319fd96dea587f82eb945f5d2a,,1,20160929

我需要将这个csv文件分成4个csv文件，其中条件是每行开头的事件号。到目前为止，我创建了一个包含所有事件号{89,90,91,92}的集合，我知道我需要在一个循环中创建循环，并将每一行复制到其专用的csv文件中。在

Answer 1

如果没有遇到第一个字段，您甚至可以通过保持该id和关联文件的映射来动态创建结果文件：

files = {}
with open('file.csv') as fd:
    for line in fd:
        if 0 == len(line.strip()): continue  # skip empty lines
        try:
            id_field = line.split(',', 1)[0] # extract first field
            if not id in files.keys():       # if not encountered open a new result file
                files[id] = open(id + '.csv')
            files[id].write(line)            # write the line in proper file
        except Exception as e:
            print('ERR', line, e)            # catchall in case of problems...