yolo标注txt文件中第一个字符改成0

import os, shutil

def change_files():

path =r"D:\Desktop\0-chognbiao"
# 用os.walk方法取得path路径下的文件夹路径，子文件夹名，所有文件名
for foldName, subfolders, filenames in os.walk(path):
    # print(filenames)
    # 遍历列表下的所有文件名

    for filename in filenames:
        txtpath = os.path.join(foldName, filename)

        with open(txtpath, 'r') as f:

            line = f.readline()

            a = line.split(' ')
            if a[0] != '0':
                a[0] = '0'
            haha = ''
            for i in a:
                haha = haha + i + ' '

            with open(txtpath, 'w') as f:
                f.write(haha)

if name == ‘main’:

change_files()