tkinter example calc (snippet)

Python tkinter (gui) example 'calc'

Modules used in program:

• import math

calc

Python tkinter example: calc

#-*-coding: utf-8-*-
from Tkinter import *
import math

class calc:
    def getandreplace(self):
        self.expression = self.e.get()
        self.newtext=self.expression.replace(self.newdiv,'/')
        self.newtext=self.newtext.replace('x','*')
    def equals(self):
        self.getandreplace()
        try:
            self.value= eval(self.newtext) #evaluate the expression using the eval function
        except SyntaxError or NameErrror:
            self.e.delete(0,END)
            self.e.insert(0,'Invalid Input!')
        else:
            self.e.delete(0,END)
            self.e.insert(0,self.value)
    def clearall(self):
        self.e.delete(0,END)
    def clear1(self):
        self.txt=self.e.get()[:-1]
        self.e.delete(0,END)
        self.e.insert(0,self.txt)

    def action(self,argi):
        self.e.insert(END,argi)
    def __init__(self,master):
        master.title('Calulator')
        master.geometry()
        self.e = Entry(master)
        self.e.grid(row=0,column=0,columnspan=6,pady=3)
        self.e.focus_set() #Sets focus on the input text area
        self.div='÷'
        self.newdiv=self.div.decode('utf-8')
        Button(master,text="=",width=10,command=lambda:self.equals()).grid(row=4, column=4,columnspan=2)
        Button(master,text='AC',width=3,command=lambda:self.clearall()).grid(row=1, column=4)
        Button(master,text='C',width=3,command=lambda:self.clear1()).grid(row=1, column=5)
        Button(master,text="+",width=3,command=lambda:self.action('+')).grid(row=4, column=3)
        Button(master,text="x",width=3,command=lambda:self.action('x')).grid(row=2, column=3)
        Button(master,text="-",width=3,command=lambda:self.action('-')).grid(row=3, column=3)
        Button(master,text="÷",width=3,command=lambda:self.action(self.newdiv)).grid(row=1, column=3)
        Button(master,text="%",width=3,command=lambda:self.action('%')).grid(row=4, column=2)
        Button(master,text="7",width=3,command=lambda:self.action('7')).grid(row=1, column=0)
        Button(master,text="8",width=3,command=lambda:self.action(8)).grid(row=1, column=1)
        Button(master,text="9",width=3,command=lambda:self.action(9)).grid(row=1, column=2)
        Button(master,text="4",width=3,command=lambda:self.action(4)).grid(row=2, column=0)
        Button(master,text="5",width=3,command=lambda:self.action(5)).grid(row=2, column=1)
        Button(master,text="6",width=3,command=lambda:self.action(6)).grid(row=2, column=2)
        Button(master,text="1",width=3,command=lambda:self.action(1)).grid(row=3, column=0)
        Button(master,text="2",width=3,command=lambda:self.action(2)).grid(row=3, column=1)
        Button(master,text="3",width=3,command=lambda:self.action(3)).grid(row=3, column=2)
        Button(master,text="0",width=3,command=lambda:self.action(0)).grid(row=4, column=0)
        Button(master,text=".",width=3,command=lambda:self.action('.')).grid(row=4, column=1)
        Button(master,text="(",width=3,command=lambda:self.action('(')).grid(row=2, column=4)
        Button(master,text=")",width=3,command=lambda:self.action(')')).grid(row=2, column=5)
#Main
root = Tk()
obj=calc(root) #object instantiated
root.mainloop()

Useful links

• Learn Tkinter: https://pythonbasics.org/tkinter/
• Wikipedia tkinter: https://en.wikipedia.org/wiki/Tkinter