最好明白清楚一些，谢谢
from tkinter import *
from math import exp,log,sin,cos,tan
class Calculator:
def init(self):
window=Tk().title("简易计算器")
frame1=Frame(window).pack()
self.e1, self.e2 = StringVar(), StringVar()
Label(frame1,text="请输入表达式：").pack()
#放置标签“请输入表达式”
Entry(frame1,textvariable = self.e1,justify = RIGHT, width=28).pack()
#第一个entry
Label(frame1,text="输出结果：").pack()
#放置标签“输出结果”
Entry(frame1,textvariable = self.e2,justify = RIGHT, width=28).pack()
#第二个entry
frame2=Frame(window)
frame2.pack()
op=[[1,2,3,'+'],[4,5,6,'-'],[7,8,9,'*'],[0,'.','=','/'],['(',')','exp','log'],['sin','cos','tan','clear']]
for i in range(6): #放置按钮
for j in range(4):
if op[i][j] == '=':
Button(frame2,text = op[i][j],command = lambda: self.e2.set(str(eval(self.e1.get()))),width=6).grid(row =i,column=j)
elif op[i][j] == 'clear':
Button(frame2,text = op[i][j],command = lambda: (self.e1.set(''),self.e2.set('')),width=6).grid(row =i,column=j)
else:
Button(frame2,text = str(op[i][j]),command = lambda w=self.e1, c=str(op[i][j]): w.set(w.get() + c),width=6).grid(row=i,column=j)
Calculator()
