用python修改文件内容修改txt内容的3种方法

方法一、修改原文件方式

def updateFile(file,old_str,new_str):
    """
    替换文件中的字符串
    :param file:文件名
    :param old_str:就字符串
    :param new_str:新字符串
    :return:
    """
    file_data = ""
    with open(file, "r", encoding="utf-8") as f:
        for line in f:
            if old_str in line:
                line = line.replace(old_str,new_str)
            file_data += line
    with open(file,"w",encoding="utf-8") as f:
        f.write(file_data)

updateFile(r"D:\zdz\myfile.txt", "zdz", "daziran")#将"D:\zdz\"路径的myfile.txt文件把所有的zdz改为daziran

方法二、python字符串替换的方法，修改文件内容，把原文件内容和要修改的内容写到新文件中进行存储的方式

import os
def updateFile(file,old_str,new_str):
    """
    将替换的字符串写到一个新的文件中，然后将原文件删除，新文件改为原来文件的名字
    :param file: 文件路径
    :param old_str: 需要替换的字符串
    :param new_str: 替换的字符串
    :return: None
    """
    with open(file, "r", encoding="utf-8") as f1,open("%s.bak" % file, "w", encoding="utf-8") as f2:
        for line in f1:
            if old_str in line:
                line = line.replace(old_str, new_str)
            f2.write(line)
    os.remove(file)
    os.rename("%s.bak" % file, file)

updateFile(r"D:\zdz\myfile.txt", "zdz", "daziran")#将"D:\zdz\"路径的myfile.txt文件把所有的zdz改为daziran

方法三、python 使用正则表达式替换文件内容 re.sub 方法替换

import re,os
def updateFile(file,old_str,new_str):
    with open(file, "r", encoding="utf-8") as f1,open("%s.bak" % file, "w", encoding="utf-8") as f2:
        for line in f1:
            f2.write(re.sub(old_str,new_str,line))
    os.remove(file)
    os.rename("%s.bak" % file, file)
    
updateFile(r"D:\zdz\myfile.txt", "zdz", "daziran")#将"D:\zdz\"路径的myfile.txt文件把所有的zdz改为daziran