Python3.x 错误2没有这样的文件或目录website_content.txt""

发布于04月02日

我得到了一个文件找不到错误，标题上的那个，我是一个初学者. 有人能帮忙吗？

import requests
import time
from bs4 import BeautifulSoup

Headers = {"user-agent":"my user-agent"}

URL = "www.myurl.com"

def monitor_website_changes():
    while True:
        r = requests.get(URL, headers=Headers)
        with open("website_content.txt", "r") as file:
            previous_content = file.read()
        if response.txt == previous_content:
            print("website content has changed")
        with open("website_content.txt", "w") as file:
            file.write(response.txt)
        time.sleep(1)

monitor_website_changes()

我正在构建一个脚本，跟踪网站的变化，尽我最大的努力，以避免urlib库，因为我的困难理解它.如果可能的话，我想解决的问题坚持使用3库之前使用.

推荐答案

我猜当你第一次运行脚本时，文件不存在，所以你得到的错误.

我对这个问题进行了一点调整:

当运行时try 加载文件内容
如果没有找到文件，返回一个伪字符串
用这个字符串定期判断网站内容
如果有变化，保存页面到文件，更新字符串并转到步骤3.

import time

import requests


def get_prev_content(filename):
    try:
        with open(filename, "r", encoding="utf-8") as f_in:
            return f_in.read()
    except FileNotFoundError:
        return "dummy"


def monitor(filename, url):
    prev_content = get_prev_content(filename)
    while True:
        time.sleep(2)

        resp = requests.get(url)
        if prev_content == resp.text:
            print(".")
            continue

        print(f"{url=} changed, writing to {filename=} !")

        with open(filename, "w", encoding="utf-8") as f_out:
            f_out.write(resp.text)

        prev_content = resp.text


url = "https://news.ycombinator.com/"
filename = "website_content.txt"

monitor(filename, url)

打印:

...

.                
.                                              
url='https://news.ycombinator.com/' changed, writing to filename='website_content.txt' !
.

...