How to create a simple Calculator with GUI in Python?

In this video it shows the steps and code to create a simple UI Calculator in Python. It uses Visual Studio Code – VS Code as editor for the Python code.

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Python Code:

import tkinter as tk
from tkinter import messagebox

# Create the main window
root = tk.Tk()
root.title("Simple Calculator")
root.geometry("500x500")

# Global variable for storing the expression
expression = ""

# Function to update the expression in the entry widget
def press(num):
    global expression
    expression += str(num)
    equation.set(expression)

# Function to evaluate the final expression
def equalpress():
    try:
        global expression
        total = str(eval(expression))
        equation.set(total)
        expression = total
    except:
        equation.set("Error")
        expression = ""

# Function to clear the expression in the entry widget
def clear():
    global expression
    expression = ""
    equation.set("")

# Entry field for showing expression/result
equation = tk.StringVar()
expression_field = tk.Entry(root, textvariable=equation, font=("Arial", 20), bd=10, insertwidth=4, width=25, borderwidth=4)
expression_field.grid(row=0, column=0, columnspan=4)

# Button layout
buttons = [
    ('7', 1, 0), ('8', 1, 1), ('9', 1, 2), ('+', 1, 3),
    ('4', 2, 0), ('5', 2, 1), ('6', 2, 2), ('-', 2, 3),
    ('1', 3, 0), ('2', 3, 1), ('3', 3, 2), ('*', 3, 3),
    ('C', 4, 0), ('0', 4, 1), ('=', 4, 2), ('/', 4, 3),
]

# Create buttons using a loop
for (text, row, col) in buttons:
    if text == '=':
        btn = tk.Button(root, text=text, height=3, width=8, font=("Arial", 18), command=equalpress)
    elif text == 'C':
        btn = tk.Button(root, text=text, height=3, width=8, font=("Arial", 18), command=clear)
    else:
        btn = tk.Button(root, text=text, height=3, width=8, font=("Arial", 18), command=lambda txt=text: press(txt))
    btn.grid(row=row, column=col)

# Start the GUI loop
root.mainloop()

Screenshots: