python没有正确显示可执行输出 [英] python not displaying executable output properly

问题描述

我正在使用代码在 Linux 终端中通过 python 执行可执行文件.

I am using code to execute an executable file via python in Linux Terminal.

我在python中使用的代码是

The code I use in python is

import subprocess


def executable_shell():
    # to run cosmo file     
    x=subprocess.run('cd .. && cd build &&  ./COSMO', shell=True, capture_output=True)
    print(x)

executable_shell()

这里COSMO是我的可执行文件要运行这个 python 文件，我使用命令:$ python3 file.py

Here COSMO is my executable file To run this python file I use command: $ python3 file.py

代码正在运行，但显示文件之间没有行间距，就像每个新行都从同一行开始，而不是跳转到新行.

The code is working but the display file is without line space between them, like each new line is starting on the same line rather than jumping to a new line.

但是如果我从终端以正常方式运行这个可执行文件

But if I run this executable in the normal way from the terminal

$ ./COSMO

我得到了正确的格式.

示例输出:

xxxxx xxxxx xx

期望的输出:

xxxxx
xxxxx
xx

推荐答案

您正在运行的代码将打印出一个人类可读的 CompletedProcess 对象表示，该对象包括但包含的内容远不止子流程的实际输出，在一行中.

The code you are running would print a human-readable representation of a CompletedProcess object which includes, but contains much more than, the actual output from your subprocess, on a single line.

Python 3.7.2 (default, Mar 25 2020, 10:15:53) 
[Clang 11.0.3 (clang-1103.0.32.29)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import subprocess
>>> x = subprocess.run(['printf', '%s
', 'foo', 'bar', 'baz'], capture_output=True)
>>> print(x)
CompletedProcess(args=['printf', '%s
', 'foo', 'bar', 'baz'], returncode=0, stdout=b'foo
bar
baz
', stderr=b'')

要实际只打印输出，请尝试

To actually print only the output, try

>>> print(x.stdout.decode())
foo
bar
baz

更好的是，让 Python 为您解码.

Better yet, have Python decode it for you.

import subprocess


def executable_shell():
    # to run cosmo file     
    x = subprocess.run(
        # Just the command, as a list of arguments, so we can avoid shell=True
        ['./COSMO'],
        # Specify which directory to run it in
        cwd='../build',
        # Throw an exception if the command fails (optional but recommended)
        check=True,
        # Have Python decode the output as text instead of raw bytes
        text=True,
        # Capture output, as before
        capture_output=True)
    return x.stdout

print(executable_shell())

注意我是如何添加 text=True 的(并且还重构为使用 check=True 并摆脱了 shell=True)以及如何该函数现在返回结果，调用者打印它(或用它做其他事情，视情况而定).通常，您希望函数返回结果而不是打印结果；这样可以更轻松地将它们重用于其他任务.

Notice how I added text=True (and also refactored to use check=True and get rid of shell=True) and how the function now returns the result, and the caller prints it (or does something else with it, as the case may be). Generally, you want functions to return results rather than print them; this makes it easier to reuse them for other tasks.

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