将这5个文件夹合并到sdf.txt文件中

import re from envs.django.Lib import os if __name__ == '__main__':     f1 = open('d:/englishbook/sdf.txt', 'a+', encoding='UTF-8')     path = 'D:\englishbook'     filelist = os.listdir(path)     print(filelist)     for i in filelist:         an = re.search('^[Tech\d\.txt]+$', str(i))         print(i)         print(an)         if an:             with open('d:/englishbook/'+str(i), 'a+', encoding='UTF-8') as file1:                 print('d:/englishbook/'+str(i))                 file1 = open('d:/englishbook/'+str(i), 'a+', encoding='UTF-8')                 file1.seek(0)                 contents = file1.read()                 f1.write(contents)