Add GUI to Front-End of Script

Quickly add a GUI allowing the user to browse for a filename if a filename is not supplied on the command line using this simple GUI. It's the best of both worlds. If you want command line, you can use it. If you don't specify, then the GUI will fire up.

import PySimpleGUI as sg
import sys

if len(sys.argv) == 1:
    event, values = sg.Window('My Script',
                    [[sg.Text('Document to open')],
                    [sg.In(), sg.FileBrowse()],
                    [sg.Open(), sg.Cancel()]]).read(close=True)
    fname = values[0]
else:
    fname = sys.argv[1]

if not fname:
    sg.popup("Cancel", "No filename supplied")
    raise SystemExit("Cancelling: no filename supplied")
else:
    sg.popup('The filename you chose was', fname)

If you really want to compress your 1-line of GUI code, you can directly access just the entered data by using this single-line-of-code solution. Dunno if it's the safest way to go, but it's certainly the most compact. Single line GUIs are fun when you can get away with them.

import PySimpleGUI as sg
import sys

if len(sys.argv) == 1:
    fname = sg.Window('My Script',
                    [[sg.Text('Document to open')],
                    [sg.In(), sg.FileBrowse()],
                    [sg.Open(), sg.Cancel()]]).read(close=True)[1][0]
else:
    fname = sys.argv[1]

if not fname:
    sg.popup("Cancel", "No filename supplied")
    raise SystemExit("Cancelling: no filename supplied")
else:
    sg.popup('The filename you chose was', fname)

---