如何让我的计算器正确输入运算符，从而代替输入的不同运算符，而不是一起输入

如何解决如何让我的计算器正确输入运算符，从而代替输入的不同运算符，而不是一起输入

我不想让计算器像这样的“ +-/ **-+”并排输入，而是想让现有的运算符替换所按的任何内容，只要数字不位于旁边即可。它。我尝试在input（）函数下使用if语句检查是否输入了运算符，然后仅输入数字。像这样

def input(x):
    if x in "+-/*.:
        output.insert('end',x)

但这使我只能在计算器中输入数字，我想先避免这种情况，然后再输入运算符，也可以像我之前在运算符中提到的那样进行操作。

from tkinter import *

window = Tk()
window.title('Calculator')

#inserts numbers or operators into output
def input(x):
    output.insert('end',x)

#clears calculator
def clear():
    output.delete('1.0','end')

#solves equations
def solve():
    equation = output.get('end -1 lines linestart','end -1 lines lineend')
    try:
        answer = eval(equation)
        output.insert('end','\n')
        output.insert('end',answer)
    except:
        output.insert('end','\n' + 'ERROR' + '\n')


#output for calculator
output = Text(window,font = 'none 12 bold',height = 2,width = 25,wrap = 'word')
output.grid(row = 0,column = 0,columnspan = 4,pady = 10)

###buttons
#clear and operators
b_clear = Button(window,text = 'C',width = 7,height = 3,command = clear)
b_clear.grid(row = 1,column = 2,padx = (10,0))

b_div = Button(window,text = '/',command = lambda: input('/'))
b_div.grid(row = 1,column = 3,padx = 10)

b_mult = Button(window,text = '*',command = lambda: input('*'))
b_mult.grid(row = 2,column = 3)

b_subt = Button(window,text = '-',command = lambda: input('-'))
b_subt.grid(row = 3,column = 3)

b_add = Button(window,text = '+',command = lambda: input('+'))
b_add.grid(row = 4,column = 3)

b_equal = Button(window,text = '=',command = solve)
b_equal.grid(row = 5,pady = (0,10))

#numbers
b_9 = Button(window,text = '9',command = lambda: input('9'))
b_9.grid(row = 2,0),pady = 10)

b_8 = Button(window,text = '8',command = lambda: input('8'))
b_8.grid(row = 2,column = 1)

b_7 = Button(window,text = '7',command = lambda: input('7'))
b_7.grid(row = 2,padx = 10)

b_6 = Button(window,text = '6',command = lambda: input('6'))
b_6.grid(row = 3,0))

b_5 = Button(window,text = '5',command = lambda: input('5'))
b_5.grid(row = 3,column = 1)

b_4 = Button(window,text = '4',command = lambda: input('4'))
b_4.grid(row = 3,column = 0)

b_3 = Button(window,text = '3',command = lambda: input('3'))
b_3.grid(row = 4,pady = 10)

b_2 = Button(window,text = '2',command = lambda: input('2'))
b_2.grid(row = 4,column = 1)

b_1 = Button(window,text = '1',command = lambda: input('1'))
b_1.grid(row = 4,column = 0)

b_0 = Button(window,text = '0',command = lambda: input('0'))
b_0.grid(row = 5,10))

b_decimal = Button(window,text = '.',command = lambda: input('.'))
b_decimal.grid(row = 5,column = 1,10))

b_negative = Button(window,text = '(-)',command = lambda: input('-'))
b_negative.grid(row = 5,10))

#run calculator
window.mainloop()