"""Today we're going to show you guys how to build a
GUI calculator using tkinter and the math libraries"""
#First we need to import the libraries
import tkinter, math
#We then need to set up a global variable
expression = ""
#A main function needs to be created
def main():
#Some functions for the buttons are now needed
def press(num):
global expression
expression += str(num)
equation.set(expression)
def equal():
try:
global expression
total = str(eval(expression))
equation.set(total)
except:
equation.set(" error ")
expression = ""
def clear():
global expression
expression = ""
equation.set(expression)
def back():
global expression
expression = expression
equation.set(expression)
def pi():
global expression
expression = str(math.pi)
equation.set(expression)
#Now a tkinter window needs to be setup
window = tkinter.Tk()
window.title("GUI calculator")
#We need to setup a couple of frames to organise it
frame1 = tkinter.Frame(master=window, width=200, height=100)
frame2 = tkinter.Frame(master=window, width=200, height=400)
frame1.grid(row=0, column=0)
frame2.grid(row=1, column=0)
"""The two lines at the end are used to place the
frames onto the window with the grid method"""
#A StringVar variable can be set up now
equation = tkinter.StringVar()
#We have to configure the rows and columns
frame2.rowconfigure([0,1,2,3,4],minsize=50,weight=1)
frame2.columnconfigure([0,1,2,3],minsize=50,weight=1)
#Now we can setup the display
display = tkinter.Entry(master=frame1, textvariable=equation)
display.pack()
"""Pack is another method use to display elements
onto the window or other widgets"""
#Now we setup each button individually
clear = tkinter.Button(master=frame2,width=2,height=2,text=
"C",command=clear)
pi = tkinter.Button(master=frame2,width=2,height=2,text=
"\u03C0",command=pi)
back = tkinter.Button(master=frame2,width=2,height=2,text=
"B",command=back)
div = tkinter.Button(master=frame2,width=2,height=2,text=
chr(247),command=lambda: press("/"))
number1 = tkinter.Button(master=frame2,width=2,height=2,text=
"1",command=lambda: press("1"))
number2 = tkinter.Button(master=frame2,width=2,height=2,text=
"2",command = lambda: press("2"))
number3 = tkinter.Button(master=frame2,width=2,height=2,text=
"3",command = lambda: press("3"))
number4 = tkinter.Button(master=frame2,width=2,height=2,text=
"4",command=lambda: press("4"))
number5 = tkinter.Button(master=frame2,width=2,height=2,text=
"5",command=lambda: press("5"))
number6 = tkinter.Button(master=frame2,width=2,height=2,text=
"6",command=lambda: press("6"))
number7 = tkinter.Button(master=frame2,width=2,height=2,text=
"7",command=lambda: press("7"))
number8 = tkinter.Button(master=frame2,width=2,height=2,text=
"8",command=lambda: press("8"))
number9 = tkinter.Button(master=frame2,width=2,height=2,text=
"9",command=lambda: press("9"))
number0 = tkinter.Button(master=frame2,width=2,height=2,text=
"0",command=lambda: press("0"))
minus = tkinter.Button(master=frame2,width=2,height=2,text=
"-",command=lambda: press("-"))
dot = tkinter.Button(master=frame2,width=2,height=2,text=
".",command=lambda: press("."))
multiply = tkinter.Button(master=frame2,width=2,height=
2,text="*",command=lambda: press("*"))
add = tkinter.Button(master=frame2,width=2,height=2,text=
"+",command=lambda: press("+"))
takeaway = tkinter.Button(master=frame2,width=2,height=
2,text="-",command=lambda: press("-"))
equal = tkinter.Button(master=frame2,width=2,height=2,text=
"=",command=equal)
#Now we have to use the grid method for each button
clear.grid(row=0, column=0)
pi.grid(row=0, column=1)
back.grid(row=0, column=2)
div.grid(row=0, column=3)
number1.grid(row=1, column=0)
number2.grid(row=1, column=1)
number3.grid(row=1, column=2)
number4.grid(row=2, column=0)
number5.grid(row=2, column=1)
number6.grid(row=2, column=2)
number7.grid(row=3, column=0)
number8.grid(row=3, column=1)
number9.grid(row=3, column=2)
number0.grid(row=4, column=1)
minus.grid(row=4, column=0)
dot.grid(row=4, column=2)
multiply.grid(row=1, column=3)
add.grid(row=2, column=3)
takeaway.grid(row=3, column=3)
equal.grid(row=4, column=3)
#So now we just need one more line
window.mainloop()
if __name__ == "__main__":
main()
#Theses last 2 lines allow us to run the program
Python Programmer