Python - 验证，写入并附加.txt文件

Question

我想验证我的抓取工具从我的.txt文件中存储的链接获取的链接。在我的抓取工具从网络检索链接后，它会将附加（'a'）到我的.txt文件中。但是，如果链接已经存在于我的.txt文件中，我想用（'w'）附加它。任何想法，我怎么能做到这一点？

def spider(targetname, DOMAIN, g_data): 
    for item in g_data: 
     try: 
      name = item.find_all("strong", {"class": "fullname show-popup-with-id "})[0].text 
      username = item.find_all("span", {"class": "username u-dir"})[0].text 
      post = item.find_all("p", {"class": "TweetTextSize TweetTextSize--normal js-tweet-text tweet-text"})[0].text 
      replies = item.find_all("span", {"class": "u-hiddenVisually"})[3].text 
      retweets = item.find_all("span", {"class": "u-hiddenVisually"})[4].text 
      likes = item.find_all("span", {"class": "u-hiddenVisually"})[5].text 
      retweetby = item.find_all("a", {"href": "/"+targetname})[0].text 
      datas = item.find_all('a', {'class':'tweet-timestamp js-permalink js-nav js-tooltip'}) 
      for data in datas: 
       link = DOMAIN + data['href'] 
       date = data['title'] 
      append_to_file(crawledfile, name, username, post, link, replies, retweets, likes, retweetby, date) 
     except: 
      pass 


`def append_to_file(path, name, username, post, link, replies, retweets, likes, retweetby, date): 
    with open(path, 'a') as file: 
     try: 
      file.write("Name: "+ name + '\n') 
     except: 
      print("Name: --Currently unavailable--" + '\n') 
     try: 
      file.write("Username: "+ username + '\n') 
     except: 
      print("Username: --Currently unavailable--" + '\n') 
     try: 
      file.write("Post: "+ post + '\n') 
     except: 
      print("Post: --Currently unavailable--" + '\n') 
     try: 
      file.write("post's link: "+ link.strip() + '\n') 
     except: 
      print("post's link: --Currently unavailable--" + '\n') 
     try: 
      file.write("Replies: "+ replies.strip() + '\n') 
     except: 
      print("Replies: --Currently unavailable--" + '\n') 
     try: 
      file.write("Retweet: "+ retweets.strip() + '\n') 
     except: 
      print("Retweet: --Currently unavailable--" + '\n') 
     try: 
      file.write("Likes: "+ likes.strip() + '\n') 
     except: 
      print("Likes: --Currently unavailable--" + '\n') 
     try: 
      if(username != "@" + targetname): 
       file.write("Retweeted By: " + retweetby.strip() + '\n') 
     except: 
      file.write("Retweeted By: --Currently unavailable--" + '\n') 
     try: 
      file.write("Date: " + date + '\n') 
     except: 
      file.write("Date: --Currently unavailable--" + '\n') 
     file.write("" + '\n')` 




Name: Donald J. Trump Username: @realDonaldTrump Post: I look forward to paying my respects to our brave men and women on this Memorial Day at Arlington National Cemetery later this morning. post's link: https://twitter.com/realDonaldTrump/status/869170615881793536 Replies: 14,333 replies Retweet: 13,492 retweets Likes: 74,645 likes Date: 5:36 AM - 29 May 2017 

Name: Donald J. Trump Username: @realDonaldTrump Post: Today we remember the men and women who made the ultimate sacrifice in serving. Thank you, God bless your families & God bless the USA! post's link: https://twitter.com/realDonaldTrump/status/869170351049240576 Replies: 8,827 replies Retweet: 33,541 retweets Likes: 123,112 likes Date: 5:35 AM - 29 May 2017 

Answer 1

如果我正确理解您的说法，您只需将字符“a”或“W”基于状态的文本文件，如果该链接已经存在的文件或不在家。为此，您可以使用以下代码：

def append_to_file(path, name, username, post, link, replies, retweets, likes, retweetby, date): 
    with open(path, 'a') as file: 
     if link.strip() in file.read(): 
      to_append = 'a' 
     else: 
      to_append = 'w' 
     try: 
      file.write("Name: " + name + to_append + '\n') 
     except: 
      print("Name: -- Currently unavailable--" + '\n') 
     try: 
      file.write("Username: " + username + to_append + '\n') 
     except: 
      print("Username: -- Currently unavailable--" + '\n') 
     try: 
      file.write("Post: " + post + to_append + '\n') 
     except: 
      print("Post: -- Currently unavailable--" + '\n') 
     try: 
      file.write("post's link: " + link.strip() + to_append + '\n') 
     except: 
      print("post's link: -- Currently unavailable--" + '\n') 
     try: 
      file.write("Replies: " + replies.strip() + to_append + '\n') 
     except: 
      print("Replies: -- Currently unavailable--" + '\n') 
     try: 
      file.write("Retweet: " + retweets.strip() + to_append + '\n') 
     except: 
      print("Retweet: -- Currently unavailable--" + '\n') 
     try: 
      file.write("Likes: " + likes.strip() + to_append + '\n') 
     except: 
      print("Likes: -- Currently unavailable--" + '\n') 
     try: 
      if(username != "@" + targetname): 
       file.write("Retweeted By: " + 
          retweetby.strip() + to_append + '\n') 
     except: 
      file.write(
       "Retweeted By: -- Currently unavailable--" + '\n') 
     try: 
      file.write("Date: " + date + to_append + '\n') 
     except: 
      file.write("Date: -- Currently unavailable--" + 
         to_append + '\n') 
     file.write("" + '\n')