python实现批量TXT文档每段结尾添加字符

import os

def Line_Add_File(file, str):

    file_data = ""
    with open(file, "r") as f:
        for line in f:
            line = line.replace("\n",'') + str + "\n" # 因为存储时候拼接字符串会出现换行，所以需要去掉末尾的换行符
            file_data = file_data + line
    with open(file, "w") as f:
        f.write(file_data)

base_dir = "C://Users//49115//Desktop//test//"
str = "1"

for root, dirs, files in os.walk(base_dir):#文档内所有文件
    for file_name in files: #文件夹下各文件名（包括子文件中）
        if file_name.endswith('.txt'):#要修改的文件类型
            filename = os.path.join(root, file_name)
            print(filename)
            Line_Add_File(filename, str)