How to give input multiple times to another program on python

Question

I want to make python file which opens two programs. This two programs have to get input from each other multiple times. I opened two programs and know how to give input to one

Answer 1

Try using write and communicate to send data to cmd_1 and cmd_2 and get the response, see https://docs.python.org/3/library/subprocess.html#popen-constructor.

for i in range(n):
    cmd_1 = subprocess.Popen("./p1",shell = True,stdin = subprocess.PIPE,stdout = subprocess.PIPE,stderr = subprocess.PIPE)
    cmd_2 = subprocess.Popen("./p2",shell = True,stdin = subprocess.PIPE,stdout = subprocess.PIPE,stderr = subprocess.PIPE)
    cmd_1.stdin.write(cmd_input[n])
    cmd_2.stdin.write(cmd_input[n])
    cmd1_stdout, cmd1_stderr = cmd_1.communicate()
    cmd2_stdout, cmd2_stderr = cmd_2.communicate()
    for line in cmd1_stdout:
        print(line.decode('ascii'))
    for line in cmd2_stdout:
        print(line.decode('ascii'))