將列表與文本文檔進行比較

Question

因此，我在我的代碼中生成了一個列表，現在我想根據現有文檔對其進行檢查，以查看在創建新文檔之前存在哪些差異。

這裏是我的嘗試：

diff = "" 
    if File2_Loc : 
     File2 = open(File2_Loc , 'r') 
     for line in R_List : 
      if line in File2 : 
       pass 
      else : 
       diff += (line.strip() + " not found in old file.\n") 
     for line in File2 : 
      if line == "***** Differences founds : *****\n" : 
       print("Compared!") 
       break 
      if line in R_List : 
       pass 
      else : 
       diff += (line.strip() + " not found in new file.\n") 
    else : 
     print("No file inputted:") 
    for line in R_List : 
     File1.write(line) 
    File1.write("***** Differences founds : *****\n") 
    if diff : 
     File1.write(diff) 
    else : 
     File1.write("None.\n") 

這裏的問題是，內R_List每一行file2中是找不到的，即使他們的100％應該是。

我已經找了一個解決方案，但我沒有看到任何解決我的問題或解決我的問題。

Answer 1

這是因爲該文件只能讀取一次。如果您調用「in」，則不會再次迭代（從當前位置「讀取」，即文件末尾）。因此，解決辦法是使用閱讀File2.readlines（）中的所有文件到內存中，「在」試穿那件事:-)

File2 = open(File2_Loc , 'r') 
    lines2 = File2.readlines() # Define the lines here 
    File2.close()    # This is also a good idea 
    for line in R_List : 
     if line in lines2 :  # Iterate over lines instead of file 
      pass 
     else : 
      diff += (line.strip() + " not found in old file.\n") 
    for line in lines2 :  # Iterate over lines instead of file 
     if line == "***** Differences founds : *****\n" : 
      print("Compared!") 
      break 
     if line in R_List : 
      pass 
     else : 
      diff += (line.strip() + " not found in new file.\n") 

解決方案2： 該解決方案採用集和運算符「 - 」對它們進行析取：

File2 = open(File2_Loc , 'r') 
    lines2 = File2.readlines() # Define the lines here 
    File2.close()    # This is also a good idea 
    not_in_file2 = list(set(R_list) - set(lines2)) 
    not_in_rlist = list(set(lines2) - set(R_list)) 
    # Finish the diff output accordingly.