title: subprocess python filenotfounderror: [winerror 2]
body: <p>I've been using Jupyter Notebook to learn <a href="https://www.kaggle.com/ntx32505/d/ludobenistant/hr-analytics/principal-component-analysis-explained/notebook" rel="noreferrer">Principal Component Analysis from kaggle</a>), but when I run this code </p>
  
  <pre><code>     from subprocess import check_output
       print(check_output(["ls", "../input"]).decode("utf8"))
  </code></pre>
  
  <p>I got an error below</p>
  
  <pre><code>FileNotFoundError Traceback (most recent call last)
  &lt;ipython-input-3-de0e39ca3ab8&gt; in &lt;module&gt;()
        1 from subprocess import check_output
  ----&gt; 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,
  --&gt; 626                **kwargs).stdout
      627 
      628 
  
  D:\Anaconda3\lib\subprocess.py in run(input, timeout, check, *popenargs, **kwargs)
      691         kwargs['stdin'] = PIPE
      692 
  --&gt; 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,
  --&gt; 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,
  -&gt; 1224                                          startupinfo)
     1225             finally:
     1226                 # Child is launched. Close the parent's copy of those pipe
  </code></pre>
  
  <p>The path is correct, and it seems that all the call from subprocess  will fail similarly.</p>
  
  <p>Does anyone have any idea why this is happening?</p>