import tkinter as tk

def create_btn(text,col,row,cs,rs,px=(1,1),py=(1,1)):   #函数生成按钮
    t=text
    t=t.replace('×','*')
    t=t.replace('÷','/')
    t=t.replace('x²','**2')
    t=t.replace('1/x','**(-1)')
    a=tk.Button(root,text=text,width=4,command=lambda:(text_print(t)))
    a.grid(column=col,row=row,columnspan=cs,rowspan=rs,padx=px,pady=py,sticky='nswe')
    return(a)

def grid_rowconfigure(*rows):   #函数填充行
    for i in rows:
        root.grid_rowconfigure(i,weight=1)
        
def grid_columnconfigure(*cols):    #函数填充列
    for i in cols:
        root.grid_columnconfigure(i,weight=1)

def bind_print(event):  #函数键盘事件输入算式
    global textchange,equal_is
    if event.keysym!='Return':
        if event.keysym=='BackSpace':
            a=str(textchange)[0:-1]
            textchange=a
        elif event.keysym=='Delete':
            textchange=''
        else:
            textchange=str(textchange)+str(event.char)
        la.configure(text=textchange)
        show_is()
        equal_is=False
    else:
        text_equal()

def text_print(x):  #函数按钮输入算式
    global textchange,equal_is
    if x!='=':
        if x=='←':
            a=str(textchange)[0:-1]
            textchange=a
        elif x=='C':
            textchange=''
        else:
            textchange=str(textchange)+str(x)
        la.configure(text=textchange)
        show_is()
        equal_is=False
    if x=='=':
        text_equal()
    
def text_equal(event=None):   #函数计算结果并上到输入框
    global textchange,equal_is
    if lab['text']!='错误' and equal_is==False:
        textchange=lab['text']
        la.configure(text=textchange)
        lab.configure(text='')
        equal_is=True

def show_is():     #显示框内容
    global textchange
    if textchange!='':
        try:
            textshow=eval(textchange)
        except (SyntaxError,TypeError,NameError):
            lab.configure(text='错误')
        else:
            lab.configure(text=textshow)
    else:
        lab.configure(text='')

root=tk.Tk()        #创建窗体
root.geometry('250x350')
root.title('计算器')
root.bind('<Key>',bind_print)

equal_is=False      #一些变量
textchange=''

la=tk.Label(root,text='',bg='white',fg='black',font=('宋体',24),anchor='w',relief='flat')  #生成输入框
la.grid(column=0,row=0,columnspan=5,rowspan=1,sticky='we')

lab=tk.Label(root,bg='white',fg='grey',height=1,font=('宋体',22),anchor='w',relief='flat')    #生成显示框
lab.grid(column=0,row=1,columnspan=5,rowspan=1,sticky='we')

btn={}                                  #生成按钮
btn['1']=create_btn('1',0,5,1,1)
btn['2']=create_btn('2',1,5,1,1)
btn['3']=create_btn('3',2,5,1,1)
btn['4']=create_btn('4',0,4,1,1)
btn['5']=create_btn('5',1,4,1,1)
btn['6']=create_btn('6',2,4,1,1)
btn['7']=create_btn('7',0,3,1,1)
btn['8']=create_btn('8',1,3,1,1)
btn['9']=create_btn('9',2,3,1,1)
btn['0']=create_btn('0',0,6,2,1)

btn['.']=create_btn('.',2,6,1,1)
btn['=']=create_btn('=',4,5,1,2)
btn['+']=create_btn('+',3,6,1,1)
btn['-']=create_btn('-',3,5,1,1)
btn['*']=create_btn('×',3,4,1,1)
btn['/']=create_btn('÷',4,4,1,1)
btn['←']=create_btn('←',1,2,1,1)

btn['C']=create_btn('C',2,2,1,1)
btn['(']=create_btn('(',3,2,1,1)
btn[')']=create_btn(')',4,2,1,1)
btn['**2']=create_btn('x²',3,3,1,1)
btn['**(-1)']=create_btn('1/x',4,3,1,1)

grid_rowconfigure(2,3,4,5,6)
grid_columnconfigure(0,1,2,3,4)

root.mainloop()