Question

我一直在使用Jupyter Notebook学习Principal Component Analysis from kaggle），但是当我运行此代码时

     from subprocess import check_output
     print(check_output(["ls", "../input"]).decode("utf8"))

我的错误低于

FileNotFoundError Traceback (most recent call last)
<ipython-input-3-de0e39ca3ab8> in <module>()
      1 from subprocess import check_output
----> 2 print(check_output(["ls", "C:/Users/wanglei/Documents/input"]).decode("utf8"))

D:\Anaconda3\lib\subprocess.py in check_output(timeout, *popenargs, **kwargs)
    624 
    625     return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
--> 626                **kwargs).stdout
    627 
    628 

D:\Anaconda3\lib\subprocess.py in run(input, timeout, check, *popenargs, **kwargs)
    691         kwargs['stdin'] = PIPE
    692 
--> 693     with Popen(*popenargs, **kwargs) as process:
    694         try:
    695             stdout, stderr = process.communicate(input, timeout=timeout)

D:\Anaconda3\lib\subprocess.py in __init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags, restore_signals, start_new_session, pass_fds)
    945                                 c2pread, c2pwrite,
    946                                 errread, errwrite,
--> 947                                 restore_signals, start_new_session)
    948         except:
    949             # Cleanup if the child failed starting.

D:\Anaconda3\lib\subprocess.py in _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, unused_restore_signals, unused_start_new_session)
   1222                                          env,
   1223                                          cwd,
-> 1224                                          startupinfo)
   1225             finally:
   1226                 # Child is launched. Close the parent's copy of those pipe

路径是正确的，似乎来自子进程的所有调用都会失败。

有谁知道为什么会这样？

Answer 1

此代码运行ls command，is available on all POSIX-conforming systems。

您使用的是Microsoft Windows。默认情况下，Microsoft Windows不符合POSIX。例如，没有ls二进制文件。因此，子流程无法找到文件ls，因此会发出FileNotFoundError。

您可以安装Microsoft's Bash on Windows，这将为您提供ls。

然而，列出目录的pythonic和更便携的方法不是首先使用子进程，而是内置os.listdir：

import os
print(os.listdir('../input'))

Answer 2

尝试通过添加cwd争论来指定工作目录，这应该可行

import os, subprocess
cwd = os.getcwd()
proc = subprocess.Popen(["ls" ,"../input"], cwd=cwd, stdout=subprocess.PIPE)
output = proc.stdout.read().decode("utf8")

Answer 3

我碰巧有同样的问题。在Windows的Jupiter Notebook上，使用Phihag提供的以下代码对我很有用。谢谢。

    import os
    print(os.listdir('../input'))

subprocess python filenotfounderror：[winerror 2]

3 个答案: