Python搜索字符串並打印下一個x行

Question

我想弄清楚如何發送shell命令，搜索一行中的字符串，並打印x行。如果我使用open來讀取文件，但是很難通過shell來完成，我能夠完成此操作。我希望能夠發送一個shell命令並使用類似的grep -A命令。有沒有Pythonic的方式來做到這一點？以下是我的可測試代碼。提前致謝。

我的代碼：

#!/usr/bin/python3 
import subprocess 

# Works when I use open to read the file: 

with open("test_file.txt", "r") as myfile: 
    for items in myfile: 
     if 'Cherry' in items.strip(): 
      for index in range(5): 
       line = next(myfile) 
       print (line.strip()) 

# Fails when I try to send the command through the shell 

command = (subprocess.check_output(['cat', 'test_file.txt'], shell=False).decode('utf-8').splitlines()) 
for items in command: 
    if 'Cherry' in items.strip(): 
     for index in range(5): 
      line = next(command) 

輸出與錯誤：

Dragonfruit 

--- Fruits --- 
Artichoke 
Arugula 

------------------------------------------------------------------------------------------ 

Traceback (most recent call last): 
    File "/media/next_line.py", line 26, in <module> 
    line = next(command) 
TypeError: 'list' object is not an iterator 

Process finished with exit code 1 

test_file.txt的內容：

--- Fruits --- 
Apple 
Banana 
Blueberry 
Cherry 
Dragonfruit 

--- Fruits --- 
Artichoke 
Arugula 
Asparagus 
Broccoli 
Cabbage 

Answer 1

使自己，而不是讓for迭代器爲你做...（可能或可能不工作，我沒有完全測試這個）

command = (subprocess.check_output(['cat', 'test_file.txt'], shell=False).decode('utf-8').splitlines()) 
iterator = iter(command) 
for items in iterator: 
    if 'Cherry' in items.strip(): 
     for index in range(5): 
      line = next(iterator)