Question

我试图找出如何发送shell命令，在一行中搜索字符串，以及打印x行数。如果我使用open来读取文件但是通过shell执行它有困难，我能够完成此操作。我希望能够发送一个shell命令并使用类似的grep -A命令。是否有Pythonic方法来做到这一点？下面是我可测试的代码。提前谢谢。

我的代码：

#!/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)

输出错误：

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的内容：

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

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

Answer 1

自己制作迭代器，而不是让for为你做...（可能有也可能无效，我没有完全测试过这个）

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)

Python搜索字符串并打印下一行x行

1 个答案: