代码中肯定还有一些思维漏洞，望参考者留言交流。

界面：

 演示视频：

代码:

1 # coding=utf-8  2 from tkinter import *  3 import math  4 import re  5   6   7 #the main gui  8 window=Tk()  9 window.title('Calculator') 10 window.geometry('450x260') 11 mainFrame=Frame(bg='black') 12  13 #-----------button click event 14 def ButtonClick(buttonText): #except '=',use to show the expression on the entry 15     global showRes,res,oneInput 16     if buttonText!='clear' and buttonText!='back': 17         oneInput.append(buttonText) 18         showRes=showRes+buttonText 19     elif buttonText=='clear': 20         showRes='' 21         oneInput.clear() 22     else: 23         if showRes!='': 24             showRes=showRes[0:len(showRes)-len(oneInput.pop())] 25     res.set(showRes) 26  27 def MultDiv(expression,op):#multiply and divid operations 28     loc=expression.index(op) 29     if op=='×' and expression[loc+1]!='-': 30         tempRes=float(expression[loc-1])*float(expression[loc+1]) 31     elif op=='÷' and expression[loc+1]!='-':#calculate divid,not:divisor is 0 32         tempRes = float(expression[loc-1])/float(expression[loc+1]) 33     elif op=='×' and expression[loc+1]=='-': 34         tempRes = -float(expression[loc - 1]) * float(expression[loc + 2]) 35         del expression[loc-1] 36     elif op == '÷' and expression[loc + 1] == '-': 37         tempRes = -float(expression[loc - 1]) / float(expression[loc + 2]) 38         del expression[loc - 1] 39     del expression[loc-1],expression[loc-1],expression[loc-1] 40     expression.insert(loc-1,str(tempRes)) 41     return expression 42  43 def SingelValueFunction(expression,loc): 44     op=expression[loc] 45     if op=='sin ': 46         if expression[loc+1]!='-': 47             temRes=math.sin(float(expression[loc+1])) 48         else: 49             temRes=math.sin(-float(expression[loc+2])) 50             del expression[loc] 51     elif op=='cos ': 52         if expression[loc+1]!='-': 53             temRes=math.cos(float(expression[loc+1])) 54         else: 55             temRes=math.cos(-float(expression[loc+2])) 56             del expression[loc] 57     elif op=='tan ': 58         if expression[loc+1]!='-': 59             temRes=math.tan(float(expression[loc+1])) 60         else: 61             temRes=math.tan(-float(expression[loc+2])) 62             del expression[loc] 63     elif op=='abs ': 64         if expression[loc+1]!='-': 65             temRes=float(expression[loc+1]) 66         else: 67             temRes=float(expression[loc+2]) 68             del expression[loc] 69     elif op=='ln ': 70         if expression[loc+1]!='-': 71             temRes=math.log(2.718281828,float(expression[loc+1])) 72         else: 73             temRes = math.log(2.718281828, -float(expression[loc + 2])) 74             del expression[loc] 75     elif op=='sqrt ': 76         if expression[loc+1]!='-': 77             temRes=math.sqrt(float(expression[loc+1])) 78         else: 79             temRes=math.sqrt(-float(expression[loc+2])) 80             del expression[loc] 81    # elif 82     del expression[loc],expression[loc] 83     expression.insert(loc,str(temRes)) 84     return expression 85  86 def Pi(expression,op): 87     loc = expression.index(op) 88     temRes = 3.1415926535 89     del expression[loc] 90     expression.insert(loc,temRes) 91     return expression 92  93 def E(expression,op): 94     loc=expression.index(op) 95     temRes=2.718281828 96     del expression[loc] 97     expression.insert(loc,str(temRes)) 98     return expression 99 100 def Factorial(expression,op):101     loc=expression.index(op)102     temRes=math.factorial(float(expression[loc-1]))103     del expression[loc-1],expression[loc-1]104     expression.insert(loc-1,str(temRes))105     return expression106 107 def Power(expression,op):108     loc=expression.index(op)109     if expression[loc+1]!='-':110         temRes=math.pow(float(expression[loc-1]),float(expression[loc+1]))111     else:112         temRes = math.pow(float(expression[loc - 1]), -float(expression[loc + 2]))113         del expression[loc-1]114     del expression[loc-1],expression[loc-1],expression[loc-1]115     expression.insert(loc-1,str(temRes))116     return expression117 118 def WithoutBracketsExpressionCalculate(strExpression):119     expression = re.findall('([\d\.]+|÷|-|\+|×+|sin |cos |tan |ln |abs |sqrt |π|e|!|\^)', strExpression)120     print(expression)121     if expression[0] == '-':  # negative number122         expression[0] = expression[0] + expression[1]123         del expression[1]124     sum=0125     #use value to replace the e and π126     while 'e' in expression:127         E(expression,'e')128     while 'π' in expression:129         Pi(expression,'π')130     # calculate single value function131     while '!' in expression:132         Factorial(expression,'!')133 134     singleValueFunctonIndexs=[]135     for i in range(len(expression)):136         if expression[i] in ['sin ','cos ','tan ','ln ','abs ','sqrt ']:137             singleValueFunctonIndexs.append(i)138     singleValueFunctonNums=len(singleValueFunctonIndexs)139     for j in range(singleValueFunctonNums):140         SingelValueFunction(expression,singleValueFunctonIndexs[singleValueFunctonNums-1-j])141 142     while '^' in expression:143         Power(expression,'^')144 145     while True:146         #calculate mul and div first147         if '×' in expression and '÷'not in expression:148             MultDiv(expression,'×')149         elif '×'not in expression and '÷'in expression:150             MultDiv(expression,'÷')151         elif '÷'in expression and '×'in expression:152             locMul=expression.index('×')153             locDiv=expression.index('÷')154             if locMul

 测试样例：