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Build your own Python desktop Application: Python GUI calculator with full code

Build your own GUI calculator using Python

Python is the most talk about general purpose programming language. It is the language of choice from simple data manipulation to Big data analysis, web development to desktop application, artificial intelligence to Machine learning. Learning Python gets really fun with real life application. In this blog we will build a real life Python desktop application, a GUI calculator.

Python GUI Calculator

The GUI calculator that we will build using Python look as follows.

Look of sample Python GUI calculator.
GUI of Calculator

Requirement for GUI Calculator

The only requirement is Python 3 and Tkinter package. It is one of the most popular Python library for creating GUI application. Most of the latest version of Python3 comes with Tkinter.

To check if Tkinter is installed properly, run the following command in Python.

import tkinter

If the above code runs without error, then you meet all the pre-requisite for making GUI calculator.

Demo of Working GUI Calculator.

Python GUI Calculator
Demo of Calculator

Complete Python3 code for GUI calculator

from tkinter import *

class Calculator:
    def __init__(self,master):
        self.master = master
        master.title("My Calculator @")
        #creating screen widget
        self.screen = Text(master, state='disabled', width=50,height= 3, background="#EAFAF1", foreground="#000000",font=("Arial",15,"bold"))
        #Screen position in window
        #initialize screen value as empty
        #create buttons
        b1 = self.createButton(7)
        b2 = self.createButton(8)
        b3 = self.createButton(9)
        b4 = self.createButton(u"\u232B",None)
        b5 = self.createButton(4)
        b6 = self.createButton(5)
        b7 = self.createButton(6)
        b8 = self.createButton(u"\u00F7")
        b9 = self.createButton(1)
        b10 = self.createButton(2)
        b11 = self.createButton(3)
        b12 = self.createButton('*')
        b13 = self.createButton('.')
        b14 = self.createButton(0)
        b15 = self.createButton('+')
        b16 = self.createButton('-')
        b17 = self.createButton('=', None,35)
        #stored all buttons in list
        buttons = [b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,b16,b17]
        #initalize counter
        #arrange buttons with grid manager
        for row in range(1,5):
            for column in range(4):
                buttons[count].grid(row = row, column= column,padx=0,pady=0)
                count +=1
                #arrange last button '=' at the bottom
    def createButton(self,val,write=True,width=8):
        #this function creates a button and takes one compulsary argument, the value that should be on the button
        return Button(self.master,text=val,command=,write),width=width,background="#ffffff",foreground ="#1f4bff",font=("times",20,"bold"))
    def click(self,text,write):
        #this function handles the actions when you
        #click a button 'write' arguement, if true
        #than value val should be written on screen,
        #if none then should not be written on screen
        if write == None:
            #Evaluates when there is an equation to be evaluated
            if text == '=' and self.equation:
                #replace the unicode values of division ./. with python division
                #symbol / using regex
                self.equation = re.sub(u"\u00F7", '/', self.equation)
                answer = str(eval(self.equation))
                self.insert_screen(answer,newline = True)
            elif text == u"\u232B":
            #add text to screen
    def clear_screen(self):
        #to clear screen
        #set equation to empty before deleteing screen
        self.equation = ''
        self.screen.configure(state = 'normal')
        self.screen.delete('1.0', END)
    def insert_screen(self, value, newline = False):
        self.screen.configure(state ='normal')
        #record every value inserted in screen
        self.equation += str(value)
        self.screen.configure(state = 'disabled')
def calci():
    #Function that creates calculator GUI
    root = Tk()
    my_gui = Calculator(root)
# Running Calculator    

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