How to capture output from Python interpreter ?

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i have used exec in python for execution some command in python

What I have tried:

resp=  'a = 4; print(\"Expected a = 4. Actual a = {} \".format(a))'
exec(resp)

now i exec this command now i want to capture through the terminal

what i tried is

proc = subprocess.Popen(['-ls','-l',],Path.home(),text=True ,stdout=subprocess.PIPE)
                try:
                    outs, errs = proc.communicate(timeout=15)
                except TimeoutExpired:
                    proc.kill()
                outs, errs = proc.communicate()

what i am geting error like below


p = subprocess.Popen('ls','-l', shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  File "C:\test\lib\subprocess.py", line 753, in __init__
    raise TypeError("bufsize must be an integer")
TypeError: bufsize must be an integer


please Can you help me?
I am using python3.8

Posted 16-Aug-22 2:27am

HelpMewithCode

Updated 16-Aug-22 3:05am

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Richard MacCutchan 16-Aug-22 9:30am

You are passing the two strings as separate arguments to Popen. But Popen requires either a single string or a list:

p = subprocess.Popen('ls -l', ...
# or
p = subprocess.Popen(['ls','-l'],

Richard MacCutchan 16-Aug-22 9:51am

What is Path.home() supposed to mean? As I already suggested, stop guessing and read the documentation.

Richard MacCutchan 17-Aug-22 7:53am

There is no ls command in Windows. It is a Unix/Linux shell command. Whatever is is you are trying to achieve with subprocess, exec etc, you really need a better understanding of how the Windows system (and Python) works.

Richard MacCutchan 17-Aug-22 8:50am

Like I said you need to get a better understanding of Windows. You cannot start a process with an internal command in Windows, you must execute "cmd.exe" and pass it the command string as its argument.

    s = subprocess.check_output(["cmd", "/c", "dir"])
    print(s)

Richard MacCutchan 17-Aug-22 11:18am

And here is a version with your Python code:

    pypath = 'C:/Users/< path to your python executable >/python'
    pyopt = '-c'
    pycmd = 'a = 4; print("Expected a = 4. Actual a = {} ".format(a))'
    output = subprocess.run([pypath, pyopt, pycmd], capture_output=True)
    print(F'{output.stdout = }')

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OriginalGriff · Answer 1 · 2022-08-16T02:53:00

Solution 1

See here: contextlib.redirect_stdout(new_target)[^]

Posted 16-Aug-22 2:53am

OriginalGriff

Comments

HelpMewithCode 16-Aug-22 9:06am

This is not what I except OriginalGriff

I have updated my code
please Can you look into this

Richard MacCutchan · Answer 2 · 2022-08-16T03:05:00

When you get an error telling you that a parameter is missing or invalid, then you should go immediately to the documentation to find out why: subprocess — Subprocess management — Python 3.10.6 documentation[^].

You also seem to be trying to run two different things. In the Python code you are trying to execute a Linux/UNIX ls shell command. In the (I assume C#) code you are trying to exec a string of Python text.

And it is not clear which of these you want to capture.