Python：創建一個文件，其中包含一個特定的字符串，不包含另一個特定的字符串

Question

我想寫一個腳本，刪除包含一個字符串的行，並保持行包含另一個。我想最後我有一個縮進錯誤，誰能看到如何解決這個問題？

import os 
import sys 

#Reading Input file 
f = open(sys.argv[1]).readlines() 

for line in f: #(read line 0 to last line of input file) 
if 'Futures' in line and 'Elec' not in line: #if string "Futures" is not there in dictionary i.e it is unique so store it into a dictionary 
#f = open("C://Python27//New_File.csv", 'w') 
#f.close() 
#opens and close new file 
nf = open("C://Python27//New_File.csv", "w") 
nf.write(data) 
nf.close() 

Answer 1

試試這個：

for line in f: 
    if 'Futures' in line and 'Elec' not in line: 
     nf = open("C://Python27//New_File.csv", "a") 
     nf.write(data) 
     nf.close() 

Answer 2

你的壓痕和邏輯都錯了，如果你繼續與w開放，你會最終有一個單一的線，你需要打開輸出文件一旦外循環寫，因爲你去：

import sys 

#Reading Input file 
with open(sys.argv[1]) as f, open("C://Python27//New_File.csv", "w") as out: 
    for line in f: #(read line 0 to last line of input file) 
     if 'Futures' in line and 'Elec' not in line: #if string "Futures" is not there in dictionary i.e it is unique so store it into a dictionary 
      out.write(line) 

你也可以遍歷文件對象，也沒有必要和理由，除非你真正需要的行列表使用readlines方法。

另一方面，您可能需要處理傳遞文件不存在或您無權讀取的情況。