csv以逗号分隔，但是我发现我写的文件里出现多列跟逗号没关系，就算去除了逗号也还是一样。

#!/usr/bin/env python
# -*- coding:utf8 -*-
# @TIME     :2019/5/18 13:39
# @Author   :17976
# @File     :piplines.py
# @Description:
import re

import pymongo
from pymongo.errors import DuplicateKeyError

import settings


class csv_write():
    def __init__(self,file_name='wenshu.csv'):
        self.file_name = file_name

    def write_item(self,item):
        with open(self.file_name, 'a+', encoding='utf-8-sig') as f:
            for value in item.values():
                if type(value) == dict:
                    for val in value.values():
                        replacedStr = str(val).replace("，",'  ')
                        f.write(f"{replacedStr}" + ',')
                else:
                    replacedStr = str(value).replace("，",'  ')
                    f.write(f"{replacedStr}" + ',')
            f.write('\n')

class mongoStore():
    def __init__(self,table_name):
        host = settings.mongo_msg["MONGODB_HOST"]
        port = int(settings.mongo_msg["MONGODB_PORT"])
        dbname = settings.mongo_msg["MONGODB_DBNAME"]
        table = table_name
        #创建数据库连接
        self.client = pymongo.MongoClient(host=host, port=port)
        # 指定数据库
        mydb = self.client[dbname]
        #  # 设置文书ID为唯一索引,避免插入重复数据
        mydb[table].ensure_index('casedocid', unique=True)
        self.post = mydb[table]

    def process_item(self, item):
       try:
           data = dict(item)
           self.post.insert(data)
           return item
       except DuplicateKeyError:
           # 索引相同,即为重复数据,捕获错误
           print('Duplicate key error collection')
           return item

    def close_client(self):
        self.client.close()

这是一篇csv文件分割的脚本，非常棒，但是跟我想要解决的问题无关，以后或许用的着：
https://www.cnblogs.com/weiqi/p/6230464.html