在文件中查找一种日期格式并替换为另一种格式

import re
from datetime import datetime

def replace_date_format(file_path):
    # 打开文件
    with open(file_path, 'r') as file:
        # 逐行读取文件内容
        for line in file:
            # 查找日期格式并替换
            match = re.search(r'(\d{4})-(\d{2})-(\d{2})', line)
            if match:
                old_date = match.group(0)
                new_date = datetime.strptime(old_date, '%Y-%m-%d').strftime('%d/%m/%Y')
                line = line.replace(old_date, new_date)
            
            # 写回文件
            with open(file_path, 'a') as output_file:
                output_file.write(line)
    
    # 关闭文件
    file.close()

# 调用函数，替换日期格式
replace_date_format('file.txt')