PySimpleGUI 中的计算器

Question

I have a simple calculator with a fixed constant and another entry to be added to the constant. I am struggling to deal with these entries(VARIABLE) being negative ie -1234 since i cast an int() on the input so clearly this leads to problems when trying to calculate the sum.

import PySimpleGUI as sg

columns = ["FIXED","VARIABLE","RESULT"]
param = (20,3) # size of the main window

def CALCULATOR():
    sg.theme('Dark Brown 1')
    listing = [sg.Text(u, size = param) for u in columns]
    core = [
    sg.Input(f"{10}", size = param),
    sg.Input(size = param,enable_events=True,key='NUMBER'),
    sg.Input(size = param)]

    mesh = [[x,y] for (x,y) in list(zip(listing, core))]
    window = sg.Window('CALCULATOR', mesh, font='Courier 12').Finalize()
    while True:
        event, values = window.read()
        if event == sg.WINDOW_CLOSED:
            break
        elif event == "SEND":
            break
        elif event == "NUMBER":
            variable = int(values['NUMBER'])
            fixed= int(values[0])
            for element, value in zip(core[2:], [variable+fixed]):
               element.update(value=value)
        else:
            print("OVER")
    window.close()
CALCULATOR()

Answer 1

You can wrap your if-statements in a try-except statement, and then handle the updates for when there is a ValueError :

while True:
    event, values = window.read()
    try:
        if event == sg.WINDOW_CLOSED:
            break
        elif event == "SEND":
            break
        elif event == "NUMBER":
            variable = int(values['NUMBER'])
            fixed = int(values[0])
            core[2].update(variable+fixed)
        else:
            print("OVER")
    except ValueError:
        core[2].update("ValueError!")

The above code "catches" the ValueError that is triggered once you input something that doesn't translate well into an integer, after that you can then update the field to inform the user why the results didn't output.