Python3多个Excel写入同一个

# -*- coding=UTF-8 -*-
import time
import requests
import re
import os
from bs4 import BeautifulSoup
from requests.exceptions import ConnectionError, ReadTimeout
import csv

def doDown():
    # 读取某个文件夹下的所有文件
    for file_name_list in os.walk('C:/Users/25308/Documents/WeChat Files/wxid_dodqfj4ugixb22/FileStorage/File/2020-01/各个国家/'):
        #print("1:", maindir)  # 当前主目录
        #print("2:", subdir)  # 当前主目录下的所有目录
        print("3:", file_name_list[2])  # 当前主目录下的所有文件
        #读取文件
        # 改变当前工作目录到指定的路径
        #print('123456')
        for filename in file_name_list[2]:
            #print(filename)
            #print('234567')
            os.chdir('C:/Users/25308/Documents/WeChat Files/wxid_dodqfj4ugixb22/FileStorage/File/2020-01/各个国家/')
            try:
                #读取文件，并打印
                print(filename)
                with open(filename, 'r') as file:
                    reader = csv.reader(file)
                    #print('22')
                    #print(type(reader))
                    for row in reader:
                        #print('33')
                        if 'No data' in row[0]:
                            print('1111:',row)
                            continue
                        if 'Cla' in row[0]:
                            print('2222:', row)
                            continue
                        else:
                            #print('写入一行')
                            with open('123.csv', 'a', encoding='utf-8-sig', newline='') as f:
                                csv_writer = csv.writer(f, delimiter=',')
                                csv_writer.writerow(row)
            except Exception as ex:
                print("出现如下异常%s" % ex, filename)
                continue
if __name__ == '__main__':
    doDown()  # 执行下载方法
    print('结束！！！！！！！！！！！！！！！！！！！！！！！！！！！！！')