How to print output from a script in gui called in another Tkinter script?

Question

I have tried using several different similar solutions that I have found online, but none seem to quite do what I am aiming for.

I want to call an external script (hel

Answer 1

You can use subprocess.check_output() to get output and assign to Label

You can also import script and execute function from script.

import test
test.function()

But first you will have to redirect sys.stdout using class with write() and then it will catch all printed text.

You can redirect sys.stdout to variable (see StdoutRedirector) and then you can edit it (ie. strip \n at the end) or you can redirect directly to Label (see StdoutRedirectorLabel)

import Tkinter as tk

# -----

import subprocess

def callback1():
    cmd = 'python test.py'

    # it will execute script which runs only `function1`
    output = subprocess.check_output(cmd, shell=True)

    lbl['text'] = output.strip()

# -----

class StdoutRedirector(object):

    def __init__(self):
        # clear before get all values
        self.result = ''

    def write(self, text):
        # have to use += because one `print()` executes `sys.stdout` many times
        self.result += text

def callback2():

    import test

    # keep original `sys.stdout
    old_stdout = sys.stdout

    # redirect to class which has `self.result`
    sys.stdout = StdoutRedirector()

    # it will execute only `function2`
    test.function2()

    # assign result to label (after removing ending "\n")
    lbl['text'] = sys.stdout.result.strip()

    # set back original `sys.stdout
    sys.stdout = old_stdout

# -----

import sys

class StdoutRedirectorLabel(object):

    def __init__(self, widget):
        self.widget = widget
        # clear at start because it will use +=
        self.widget['text'] = ''

    def write(self, text):
        # have to use += because one `print()` executes `sys.stdout` many times
        self.widget['text'] += text

def callback3():

    import test

    # keep original `sys.stdout
    old_stdout = sys.stdout

    # redirect to class which will add text to `lbl`
    sys.stdout = StdoutRedirectorLabel(lbl)

    # it will execute only `function3` and assign result to Label (with ending "\n")
    test.function3()

    # set back original `sys.stdout
    sys.stdout = old_stdout

# --- main ---

master = tk.Tk()
master.geometry('200x200')

lbl = tk.Label(master, text='')
lbl.pack()

btn1 = tk.Button(master, text="subprocess", command=callback1)
btn1.pack()

btn2 = tk.Button(master, text="StdoutRedirector", command=callback2)
btn2.pack()

btn3 = tk.Button(master, text="StdoutRedirectorLabel", command=callback3)
btn3.pack()

master.mainloop()

test.py

def function1():
    print('function 1')

def function2():
    print('function 2')

def function3():
    print('function 3')

if __name__ == '__main__':
    function1()