检查文本文件的内容，如果不存在则添加内容

Question

我是python的新手。我正在使用 python 设计一个报价应用程序。我使用 BeautifulSoup 从聪明的报价网站获取当天的报价。我会将它附加到文本文件中。在这里，如果当天的报价已经添加，当我再次执行程序时，它应该跳过它。如何使它成为可能

这是代码：

from bs4 import BeautifulSoup

import socket

import requests

import subprocess

import datetime

def quotenotify():

    timestamp = datetime.datetime.now().strftime("%b %d")

    res = requests.get('https://www.brainyquote.com/quote_of_the_day')

    soup = BeautifulSoup(res.text, 'lxml')

    image_quote = soup.find('img', {'class': 'p-qotd bqPhotoDefault bqPhotoDefaultFw img-responsive delayedPhotoLoad'})

    quoteday=image_quote['alt']

    text_file = open("quotes.log", "a+")

    text_file.write("%s"%timestamp+"\t"+"%s"% quoteday)

    text_file.write("\n")

    text_file.close()

    return

quotenotify()

在文件中输出：

Mar 29  Where there is a great love, there are always wishes. - Willa Cather

Mar 29  Where there is great love, there are always wishes. - Willa Cather

Answer 1

继续评论：from bs4 import BeautifulSoupimport requestsimport datetimedef quotenotify():    timestamp = datetime.datetime.now().strftime("%b %d")    res = requests.get('https://www.brainyquote.com/quote_of_the_day')    soup = BeautifulSoup(res.text, 'lxml')    image_quote = soup.find('img', {'class': 'p-qotd bqPhotoDefault bqPhotoDefaultFw img-responsive delayedPhotoLoad'})['alt']    with open("quotes.log", "w+") as f:        if image_quote not in f.read():            f.write("%s"%timestamp+"\t"+"%s"% image_quote + "\n")quotenotify()编辑：由于使用该模式w+会截断文件，我建议使用 pathlib：from bs4 import BeautifulSoupimport requestsimport datetimefrom pathlib import Pathdef quotenotify():    timestamp = datetime.datetime.now().strftime("%b %d")    res = requests.get('https://www.brainyquote.com/quote_of_the_day')    soup = BeautifulSoup(res.text, 'lxml')    image_quote = timestamp + "\t" + soup.find('img', {'class': 'p-qotd bqPhotoDefault bqPhotoDefaultFw img-responsive delayedPhotoLoad'})['alt']    with open("quotes3.log", "a+") as f:        contents = [Path("quotes3.log").read_text()]        print(contents)        print(image_quote)        if image_quote not in contents:            f.write("%s" % timestamp + "\t" + "%s" % image_quote + "\n")quotenotify()

Answer 2

您应该首先以读取模式打开文件并将内容加载到变量中。您可以在下面的示例中看到，我将内容加载到变量中，然后仅当变量不在文本文件中时才附加到文件中。text_file = open('test-file.txt', 'r+')read_the_file = text_file.read()text_file.close()text_file = open('test-file.txt', 'a+')new_string = 'Smack Alpha learns python'if new_string not in read_the_file:    text_file.write(new_string + '\n')text_file.close()