用tkinter实现一个简单计算器，可以进行加减乘除，支持小数点，多次运算，由lable和button构成，用grid布局

好的，以下是一个简单的计算器示例代码：

import tkinter as tk

class Calculator:
    def __init__(self, master):
        self.master = master
        master.title("Calculator")
        master.resizable(False, False)

        self.result_var = tk.StringVar()

        result_label = tk.Label(master, textvariable=self.result_var, width=20, anchor="e", bg="white")
        result_label.grid(row=0, column=0, columnspan=4, padx=5, pady=5)

        button_clear = tk.Button(master, text="C", width=5, height=2, command=self.clear)
        button_clear.grid(row=1, column=0)

        button_divide = tk.Button(master, text="/", width=5, height=2, command=lambda: self.operation("/"))
        button_divide.grid(row=1, column=1)

        button_multiply = tk.Button(master, text="*", width=5, height=2, command=lambda: self.operation("*"))
        button_multiply.grid(row=1, column=2)

        button_minus = tk.Button(master, text="-", width=5, height=2, command=lambda: self.operation("-"))
        button_minus.grid(row=1, column=3)

        button_7 = tk.Button(master, text="7", width=5, height=2, command=lambda: self.number(7))
        button_7.grid(row=2, column=0)

        button_8 = tk.Button(master, text="8", width=5, height=2, command=lambda: self.number(8))
        button_8.grid(row=2, column=1)

        button_9 = tk.Button(master, text="9", width=5, height=2, command=lambda: self.number(9))
        button_9.grid(row=2, column=2)

        button_plus = tk.Button(master, text="+", width=5, height=2, command=lambda: self.operation("+"))
        button_plus.grid(row=2, column=3)

        button_4 = tk.Button(master, text="4", width=5, height=2, command=lambda: self.number(4))
        button_4.grid(row=3, column=0)

        button_5 = tk.Button(master, text="5", width=5, height=2, command=lambda: self.number(5))
        button_5.grid(row=3, column=1)

        button_6 = tk.Button(master, text="6", width=5, height=2, command=lambda: self.number(6))
        button_6.grid(row=3, column=2)

        button_equal = tk.Button(master, text="=", width=5, height=2, command=self.calculate)
        button_equal.grid(row=3, column=3)

        button_1 = tk.Button(master, text="1", width=5, height=2, command=lambda: self.number(1))
        button_1.grid(row=4, column=0)

        button_2 = tk.Button(master, text="2", width=5, height=2, command=lambda: self.number(2))
        button_2.grid(row=4, column=1)

        button_3 = tk.Button(master, text="3", width=5, height=2, command=lambda: self.number(3))
        button_3.grid(row=4, column=2)

        button_decimal = tk.Button(master, text=".", width=5, height=2, command=lambda: self.number("."))
        button_decimal.grid(row=5, column=0)

        button_0 = tk.Button(master, text="0", width=5, height=2, command=lambda: self.number(0))
        button_0.grid(row=5, column=1)

        button_exit = tk.Button(master, text="Exit", width=5, height=2, command=master.quit)
        button_exit.grid(row=5, column=2)

        button_plus_minus = tk.Button(master, text="+/-", width=5, height=2, command=self.plus_minus)
        button_plus_minus.grid(row=5, column=3)

        self.reset()

    def reset(self):
        self.first_number = None
        self.second_number = None
        self.operation_type = None
        self.result_var.set("0")
        self.is_decimal = False

    def clear(self):
        self.reset()

    def number(self, num):
        if num == ".":
            if self.is_decimal:
                return
            self.is_decimal = True
        if self.operation_type is None:
            if self.first_number is None:
                self.first_number = str(num)
            else:
                self.first_number += str(num)
            self.result_var.set(self.first_number)
        else:
            if self.second_number is None:
                self.second_number = str(num)
            else:
                self.second_number += str(num)
            self.result_var.set(self.second_number)

    def operation(self, op):
        self.operation_type = op
        self.is_decimal = False

    def plus_minus(self):
        if self.operation_type is None:
            self.first_number = str(-float(self.first_number))
            self.result_var.set(self.first_number)
        else:
            self.second_number = str(-float(self.second_number))
            self.result_var.set(self.second_number)

    def calculate(self):
        if self.first_number is None or self.second_number is None or self.operation_type is None:
            return
        if self.operation_type == "+":
            result = float(self.first_number) + float(self.second_number)
        elif self.operation_type == "-":
            result = float(self.first_number) - float(self.second_number)
        elif self.operation_type == "*":
            result = float(self.first_number) * float(self.second_number)
        elif self.operation_type == "/":
            result = float(self.first_number) / float(self.second_number)
        self.result_var.set(str(result))
        self.reset()

root = tk.Tk()
calculator = Calculator(root)
root.mainloop()

运行上述代码，将会弹出一个简单的计算器界面。