Python子进程:在进程终止后获取所有标准输出数据

在伪代码中:

• 打开子流程
• 让程序完成

我尝试了以下方法:

import subprocess
p = subprocess.Popen([cmd], 
stdout=subprocess.PIPE,stdin=subprocess.PIPE)
p.stdin.write(str(data))
p.stdin.close()
p.wait()
result = p.communicate()[0]

但是,我得到以下堆栈跟踪:

    result = p.communicate()[0]
  File "/usr/lib64/python2.7/subprocess.py", line 800, in communicate .
    return self._communicate(input)
  File "/usr/lib64/python2.7/subprocess.py", line 1396, in _communicate
    self.stdin.flush()
  ValueError: I/O operation on closed file

请告知