Python implementation of a simple calculator function

In this article, we share the example of python to achieve a simple calculator specific code for your reference, the specific content is as follows

Today I learned about the interface design part of python, and a few common graphical interface libraries are Jython, wxPython and tkinter.

The main introduction to the tkinter module, the tkinter module (tk interface) is an interface to Python's standard tk GUI toolkit. tk and tkinter can be used under most UNIX platforms, and can be applied equally well to Windows and Macintosh systems. subsequent versions of Tk 8.0 enable native window styles, and run well tk and tkinter can be used on most UNIX platforms as well as Windows and Macintosh.

The following calculator function is completed using the tkinter design.

(1) First present the initial interface of the calculator:

(2) Simple explanation: the basic functions of the calculator have been realized.

(3) Major code descriptions:

①Import Package

import tkinter
from tkinter import *
import re
import

②Interface Layout Settings

# Create the main window
root = Tk()
# Set window size and position
("--- Calculator---")
("320x210+500+200")
# Auto-refresh string variables with set and get methods for passing and retrieving values
contentVar = (root,'')
# Create single line text boxes
contentEntry = (root, textvariable=contentVar)
# Set the coordinates and width of the text box
(x=20, y=10, width=260, height=30)
 
# Button display content
bvalue = ['CLC', '+', '-', '//', '0', '1', '2', '√', '3', '4', '5', '*', '6', '7', '8', '.', '9', '/', '**', '=']
index = 0
# 5x4 placement of buttons
for row in range(5):
    for col in range(4):
        d = bvalue[index]
        index += 1
        btnDigit = (root, text=d, command=lambda x=d:onclick(x))
        (x=20 + col * 70, y=50 + row * 30, width=50, height=20)
()

③ Response function for button events (can be exchanged in the comment section)

# Click events
def onclick(btn)：
    # Operators
    operation = ('+', '-', '*', '/', '**', '//')
    # Get the contents of the text box
    content = ()
    # If the existing content begins with a decimal point, precede it with 0
    if ('.'):
        content = '0' + content  # Strings can be augmented with characters directly with +
    # Respond differently to different buttons
    if btn in '0123456789':
        # Press 0-9 to append to content
        content += btn
    elif btn == '.':
        # Split the content from the +-*/ characters.
        lastPart = (r'\+|-|\*|/', content)[-1]
        if '.' in lastPart:
            # Information Alert dialog box
            ('Error', 'Recurring decimal points')
            return
        else:
            content += btn
    elif btn == 'CLC':
        # Clear the text box
        content = ''
    elif btn == '=':
        try:
            # Evaluate the input expression
            content = str(eval(content))
        except:
            ('Error', 'The expression is wrong')
            return
    elif btn in operation:
        if (operation):
            ('Error', 'Continuous operators are not allowed')
            return
        content += btn
    elif btn == '√':
        # Split from . Split at n, n is a list
        n = ('.')
        # If all the ones in the list are numbers, it's to check if the expression is the right one
        if all(map(lambda x: (), n)):
            content = eval(content) ** 0.5
        else:
            ('Error', 'Expression error')
            return

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