Subprocess stdin input [duplicate]

Question

I'm trying to pass arguments to my test_script.py but I'm getting the following error. I know this isn't the best way to do this but it's the only one that will work since I won't know what functions are in test_script.py. How can I pass arguments as stdin input?

test_script.py

a = int(input()) b = int(input()) print(a+b)

main_script.py

try: subprocess.check_output(['python', 'test_script.py', "2", "3"], stderr=subprocess.STDOUT) except subprocess.CalledProcessError as e: print(e.output)

Error

b'Traceback (most recent call last):\r\n File "test_script.py", line 1, in <module>\r\n a = int(input())\r\nEOFError: EOF when reading a line\r\n'

in main_script you are passing numbers as argument but in test_script you are trying to read them from stdin — Saeid
– Saeid, Commented Nov 28, 2015 at 20:34
A script that test other scripts, you type input data and read the output, an if you know correct output you can see if the script is working properly — Nobbie
– Nobbie, Commented Nov 28, 2015 at 21:10

Community · Accepted Answer · 2017-05-23 12:23:37Z

If do not want to use argv, however is odd, consider Popen and operating/communicating on stdin/stdout

from subprocess import Popen, PIPE, STDOUT p = Popen(['python', 'test_script.py'], stdout=PIPE, stdin=PIPE, stderr=STDOUT) p_stdout = p.communicate(input=b'1\n2\n')[0] # python 2 # p_stdout = p.communicate(input='1\n2\n')[0] print(p_stdout.decode('utf-8').strip()) # python2 # print(p_stdout)

As a reference from SO Python subprocess and user interaction.

And even more info on https://pymotw.com/2/subprocess/

I'm getting error: p_stdout = p.communicate(input='1\n2\n')[0] File "C:\Python34\lib\subprocess.py", line 959, in communicate stdout, stderr = self._communicate(input, endtime, timeout) File "C:\Python34\lib\subprocess.py", line 1195, in _communicate self.stdin.write(input) TypeError: 'str' does not support the buffer interface

sstevan · Accepted Answer · 2015-11-28 20:37:29Z

Not sure what are you trying to do but here is one working example:

import sys # print('Number of arguments:', len(sys.argv), 'arguments.') # print('Argument List:', str(sys.argv)) # print(sys.argv[1]) # print(sys.argv[2]) a = int(sys.argv[1]) b = int(sys.argv[2]) print(a+b)

And your main_script.py:

import subprocess try: out = subprocess.check_output(['python', 'test_script.py', "2", "3"], stderr=subprocess.STDOUT) print(out) except subprocess.CalledProcessError as e: print(e.output)

This works but it uses sys.argv, is there any way for this to work with input(), or to change input() to sys.argv

Arunas V. · Accepted Answer · 2015-11-28 20:39:52Z

That is jot going to work, test_script.py expects for keyboard input not the argument.

If you want main_script.py to pass arguments to test_script.py you have to amend test_script.py below code should do the trick

import sys args = sys.argv[1:] for arg in args: print arg

otherwise you can chek argparse https://docs.python.org/2/library/argparse.html

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Subprocess stdin input [duplicate]

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