Ytdyklly

After a bit of a break away from any coding, I decided to return with something simple. As I haven't done much of GUI programming with python, and I would like to do more, I decided to make a simple calculator. If anyone is so kind, I'd like some feedback on anything that might be improved. If it makes a difference in how you'd give feedback, I consider myself an intermediate python coder (whether that's actually true remains to be seen). Some things I'm curious about in particular:

• Logic - Am I using any convoluted chains of logic that can be simplified?


• General Style - I've attempted to adhere to PEP8


• Key bindings - Is there a more effective way to bind so many keys?


• Bugs - Did I add in some unnoticed "features"? How can I avoid them in the future?


• (Opinion based) Tkinter: Even a good choice/something to pursue?

import tkinter as tk



from decimal import Decimal

from tkinter import ttk





class Calculator(ttk.Frame):

  def __init__(self, master=tk.Tk()):

    super().__init__(master)

    self.master = master

    self.master.title("tKalculator")

    self.operator = None

    self.prev_num = 0

    self.completed_calculation = False

    self.grid()



    self.create_widgets()

    self.bind_keys()

    self.arrange_widgets()



    self.mainloop()



  def create_widgets(self):

    """

    Create all calculator buttons

    and widgets

    """



    self.number_buttons = 



    # Number display

    self.top_display_space = ttk.Label(self, text=" ")

    self.display = tk.Text(self, height=1, width=30, pady=4)

    self.display.insert(1.0, "0")

    self.display["state"] = "disabled"

    self.bottom_display_space = ttk.Label(self, text=" ")



    # Number buttons

    for num in range(0, 10):

      num = str(num)

      self.number_buttons.append(

        # note to self: The num=num is necessary here

        ttk.Button(self, text=num, command=lambda num=num: self.update(num))

                                 )



    self.decimal_button = ttk.Button(self, text=".",

                    command=lambda: self.update("."))



    # Special Buttons

    self.clearall_button = ttk.Button(self, text="A/C", command=self.all_clear)

    self.clear_button = ttk.Button(self, text="C", command=self.clear)



    # Math operators

    self.add_button  = ttk.Button(self, text="+", command=lambda: self.math("+"))

    self.sub_button  = ttk.Button(self, text="-", command=lambda: self.math("-"))

    self.mult_button = ttk.Button(self, text="X", command=lambda: self.math("x"))

    self.div_button  = ttk.Button(self, text="/", command=lambda: self.math("/"))

    self.eql_button  = ttk.Button(self, text="=", command=lambda: self.math("="))



  def arrange_widgets(self):

    """

    Arrange all calculator widgets.

    """



    # Display

    self.top_display_space.grid(row=0, column=1)

    self.display.grid(row=1, column=0, columnspan=5)

    self.bottom_display_space.grid(row=2, column=2)



    # Number buttons

    row = 3

    column = 1

    for i in range(1, 10):

      self.number_buttons[i].grid(row=row, column=column)

      column += 1

      if column > 3:

        column = 1

        row += 1



    self.number_buttons[0].grid(row=6, column=2)

    self.decimal_button.grid(row=6, column=1)



    # Special Buttons

    self.clearall_button.grid(row=7, column=1)

    self.clear_button.grid(row=6, column=3)



    # Math operator buttons

    self.add_button.grid(row=7, column=2)

    self.sub_button.grid(row=7, column=3)

    self.mult_button.grid(row=8, column=2)

    self.div_button.grid(row=8, column=3)

    self.eql_button.grid(row=8, column=1)



  def bind_keys(self):

  """

  Binds events to keyboard button presses.

  """



    # Numbers

    self.master.bind("1", self.keypress_handler)

    self.master.bind("<KP_1>", self.keypress_handler)

    self.master.bind("2", self.keypress_handler)

    self.master.bind("<KP_2>", self.keypress_handler)

    self.master.bind("3", self.keypress_handler)

    self.master.bind("<KP_3>", self.keypress_handler)

    self.master.bind("4", self.keypress_handler)

    self.master.bind("<KP_4>", self.keypress_handler)

    self.master.bind("5", self.keypress_handler)

    self.master.bind("<KP_5>", self.keypress_handler)

    self.master.bind("6", self.keypress_handler)

    self.master.bind("<KP_6>", self.keypress_handler)

    self.master.bind("7", self.keypress_handler)

    self.master.bind("<KP_7>", self.keypress_handler)

    self.master.bind("8", self.keypress_handler)

    self.master.bind("<KP_8>", self.keypress_handler)

    self.master.bind("9", self.keypress_handler)

    self.master.bind("<KP_9>", self.keypress_handler)

    self.master.bind("0", self.keypress_handler)

    self.master.bind("<KP_0>", self.keypress_handler)

    self.master.bind(".", self.keypress_handler)

    self.master.bind("<KP_Decimal>", self.keypress_handler)



    # Special buttons

    self.master.bind("c", self.keypress_handler)

    self.master.bind("a", self.keypress_handler)

    self.master.bind("C", self.keypress_handler)

    self.master.bind("A", self.keypress_handler)

    self.master.bind("<BackSpace>", self.backspace)



    # Math operator buttons

    self.master.bind("+", self.keypress_handler)

    self.master.bind("-", self.keypress_handler)

    self.master.bind("*", self.keypress_handler)

    self.master.bind("x", self.keypress_handler)

    self.master.bind("/", self.keypress_handler)

    self.master.bind("<KP_Add>", self.keypress_handler)

    self.master.bind("<KP_Subtract>", self.keypress_handler)

    self.master.bind("KP_Multiply>", self.keypress_handler)

    self.master.bind("<KP_Divide>", self.keypress_handler)



    # Attempt to math

    self.master.bind("<KP_Enter>", self.keypress_handler)

    self.master.bind("<Return>", self.keypress_handler)

    self.master.bind("=", self.keypress_handler)



    # Escape to close the calculator

    self.master.bind("<Escape>", self.keypress_handler)



  def backspace(self, event):

  """

  Remove one character from the display.

  """



    self.display["state"] = "normal"

    current = self.display.get(1.0, tk.END)

    self.display.delete(1.0, tk.END)

    current = current[:-2]



    # Make sure that the display is never empty

    if current == "":

      current = "0"



    self.display.insert(1.0, current)

    self.display["state"] = "disabled"



  def keypress_handler(self, event):

  """

  Handles any bound keyboard presses.

  """



    char_keycode = '01234567890.'

    char_operator = "+-x*/"



    if (event.char in char_keycode):

      self.update(event.char)



    elif event.char in char_operator:

      self.math(event.char)



    elif event.char == "r" or event.char == "=":

      self.math("=")



    elif event.char == "x1b":

      self.master.destroy()



    elif event.char == "c" or event.char == "C":

      self.clear()



    elif event.char == "a" or event.char == "A":

      self.all_clear()



  def update(self, character):

  """

  Handles all updating of the number display.

  """

    # Allow editing of the display

    self.display["state"] = "normal"



    # Get the current number

    num = self.display.get(1.0, tk.END)

    # clear the display

    self.display.delete(1.0, tk.END)



    # Remove "n"

    num = num.strip()



    # Clear num provided we're not putting a 

    # decimal after a zero

    if num == "0" and not character == ".":

      num = ""



    num = f"{num}{character}"



    self.display.insert(1.0, f"{num}")

    self.display["state"] = "disabled"



  def all_clear(self):

  """

  Resets everything for starting a

  new calculation.

  """

    self.clear()

    self.prev_num = 0

    self.operator = None



  def clear(self):

  """

  Clears the display by removing

  any current text and setting the

  display to 0

  """

    self.display["state"] = "normal"

    self.display.delete(1.0, tk.END)

    self.display.insert(1.0, "0")

    self.display["state"] = "disabled"



  def math(self, operator):

  """

  Handle any actual math.

  """

    if not self.operator:

      # If an operator doesn't exist, the

      # calculator is waiting for a new 

      # input.

      self.operator = operator

      self.prev_num = self.display.get(1.0, tk.END)

      self.clear()



    else:

      # The calculator is ready to do some math.

      self.prev_num = Decimal(self.prev_num)

      curr_num = self.display.get(1.0, tk.END)

      curr_num = Decimal(curr_num)



      if self.operator == "+":

        self.prev_num += curr_num

      elif self.operator == "-":

        self.prev_num -= curr_num

      elif self.operator == "x":

        self.prev_num *= curr_num

      elif self.operator == "/":

        self.prev_num /= curr_num



      self.operator = operator



      if self.operator == "=":

        # It's now time to show the current result

        # of all calculations.

        self.display["state"] = "normal"

        self.display.delete(1.0, tk.END)

        self.display.insert(1.0, str(self.prev_num))

        self.display["state"] = "disabled"

        self.completed_calculation = True

      else:

        # We're ready for another number to

        # perform calculations on

        self.clear()



if __name__ == "__main__":

  calc = Calculator()

I realized a while after posting that there is a better way to bind the keys: A for loop (duh). While I've implemented that in my updated code, I've kept the original here.