如何用 Python 写一个带 GUI 的科学计算程序

　　使用Tkinter图形库，如果你是用的linux系统 记得将第一行改为from tkinter import *
　　这个代码实现的挺简单，并不是很复杂的科学计算器界面，你可以以此为基础，添加自己想要的东西：给你个截图：
　　代码是如下， 我就不给你添注释了啊：
　　#!/usr/bin/env python3.4
　　from Tkinter import *
　　import parser
　　root = Tk()
　　root.title('Calculator')
　　i = 0
　　def factorial():
　　"""Calculates the factorial of the number entered."""
　　whole_string = display.get()
　　number = int(whole_string)
　　fact = 1
　　counter = number
　　try:
　　while counter > 0:
　　fact = fact*counter
　　counter -= 1
　　clear_all()
　　display.insert(0, fact)
　　except Exception:
　　clear_all()
　　display.insert(0, "Error")
　　def clear_all():
　　"""clears all the content in the Entry widget"""
　　display.delete(0, END)
　　def get_variables(num):
　　"""Gets the user input for operands and puts it inside the entry widget"""
　　global i
　　display.insert(i, num)
　　i += 1
　　def get_operation(operator):
　　"""Gets the operand the user wants to apply on the functions"""
　　global i
　　length = len(operator)
　　display.insert(i, operator)
　　i += length
　　def undo():
　　"""removes the last entered operator/variable from entry widget"""
　　whole_string = display.get()
　　if len(whole_string): ## repeats until
　　## now just decrement the string by one index
　　new_string = whole_string[:-1]
　　print(new_string)
　　clear_all()
　　display.insert(0, new_string)
　　else:
　　clear_all()
　　display.insert(0, "Error, press AC")
　　def calculate():
　　"""
　　Evaluates the expression
　　ref : http://stackoverflow.com/questions/594266/equation-parsing-in-python
　　"""
　　whole_string = display.get()
　　try:
　　formulae = parser.expr(whole_string).compile()
　　result = eval(formulae)
　　clear_all()
　　display.insert(0, result)
　　except Exception:
　　clear_all()
　　display.insert(0, "Error!")
　　root.columnconfigure(0,pad=3)
　　root.columnconfigure(1,pad=3)
　　root.columnconfigure(2,pad=3)
　　root.columnconfigure(3,pad=3)
　　root.columnconfigure(4,pad=3)
　　root.rowconfigure(0,pad=3)
　　root.rowconfigure(1,pad=3)
　　root.rowconfigure(2,pad=3)
　　root.rowconfigure(3,pad=3)
　　display = Entry(root, font = ("Calibri", 13))
　　display.grid(row = 1, columnspan = 6 , sticky = W+E)
　　one = Button(root, text = "1", command = lambda : get_variables(1), font=("Calibri", 12))
　　one.grid(row = 2, column = 0)
　　two = Button(root, text = "2", command = lambda : get_variables(2), font=("Calibri", 12))
　　two.grid(row = 2, column = 1)
　　three = Button(root, text = "3", command = lambda : get_variables(3), font=("Calibri", 12))
　　three.grid(row = 2, column = 2)
　　four = Button(root, text = "4", command = lambda : get_variables(4), font=("Calibri", 12))
　　four.grid(row = 3 , column = 0)
　　five = Button(root, text = "5", command = lambda : get_variables(5), font=("Calibri", 12))
　　five.grid(row = 3, column = 1)
　　six = Button(root, text = "6", command = lambda : get_variables(6), font=("Calibri", 12))
　　six.grid(row = 3, column = 2)
　　seven = Button(root, text = "7", command = lambda : get_variables(7), font=("Calibri", 12))
　　seven.grid(row = 4, column = 0)
　　eight = Button(root, text = "8", command = lambda : get_variables(8), font=("Calibri", 12))
　　eight.grid(row = 4, column = 1)
　　nine = Button(root , text = "9", command = lambda : get_variables(9), font=("Calibri", 12))
　　nine.grid(row = 4, column = 2)
　　cls = Button(root, text = "AC", command = clear_all, font=("Calibri", 12), foreground = "red")
　　cls.grid(row = 5, column = 0)
　　zero = Button(root, text = "0", command = lambda : get_variables(0), font=("Calibri", 12))
　　zero.grid(row = 5, column = 1)
　　result = Button(root, text = "=", command = calculate, font=("Calibri", 12), foreground = "red")
　　result.grid(row = 5, column = 2)
　　plus = Button(root, text = "+", command = lambda : get_operation("+"), font=("Calibri", 12))
　　plus.grid(row = 2, column = 3)
　　minus = Button(root, text = "-", command = lambda : get_operation("-"), font=("Calibri", 12))
　　minus.grid(row = 3, column = 3)
　　multiply = Button(root,text = "*", command = lambda : get_operation("*"), font=("Calibri", 12))
　　multiply.grid(row = 4, column = 3)
　　divide = Button(root, text = "/", command = lambda : get_operation("/"), font=("Calibri", 12))
　　divide.grid(row = 5, column = 3)
　　# adding new operations
　　pi = Button(root, text = "pi", command = lambda: get_operation("*3.14"), font =("Calibri", 12))
　　pi.grid(row = 2, column = 4)
　　modulo = Button(root, text = "%", command = lambda : get_operation("%"), font=("Calibri", 12))
　　modulo.grid(row = 3, column = 4)
　　left_bracket = Button(root, text = "(", command = lambda: get_operation("("), font =("Calibri", 12))
　　left_bracket.grid(row = 4, column = 4)
　　exp = Button(root, text = "exp", command = lambda: get_operation("**"), font = ("Calibri", 10))
　　exp.grid(row = 5, column = 4)
　　## To be added :
　　# sin, cos, log, ln
　　undo_button = Button(root, text = "<-", command = undo, font =("Calibri", 12), foreground = "red")
　　undo_button.grid(row = 2, column = 5)
　　fact = Button(root, text = "x!", command = factorial, font=("Calibri", 12))
　　fact.grid(row = 3, column = 5)
　　right_bracket = Button(root, text = ")", command = lambda: get_operation(")"), font =("Calibri", 12))
　　right_bracket.grid(row = 4, column = 5)
　　square = Button(root, text = "^2", command = lambda: get_operation("**2"), font = ("Calibri", 10))
　　square.grid(row = 5, column = 5)
　　root.mainloop()