subprocess python filenotfounderror: [winerror 2]

Question

I've been using Jupyter Notebook to learn Principal Component Analysis from kaggle), but when I run this code

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

I got an error below

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

The path is correct, and it seems that all the call from subprocess will fail similarly.

Does anyone have any idea why this is happening?

Answer 1

This code runs the ls command, which is available on all POSIX-conforming systems.

You are using Microsoft Windows. Microsoft Windows does not conform to POSIX by default. For instance, there is no ls binary. Therefore, subprocess cannot find the file ls, and thus emits a FileNotFoundError.

You can install Microsoft's Bash on Windows, which will give you ls.

However, the pythonic and more portable way to list a directory is not to use subprocess in the first place, but the built-in os.listdir:

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