python基础： day4作业计算器

作业：计算器开发

实现加减乘除及拓号优先级解析

用户输入 1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )等类似公式后，必须自己解析里面的(),+,-,*,/符号和公式，运算后得出结果，结果必须与真实的计算器所得出的结果一致

一、说明：

有一点bug就是不能计算幂次方,如:'6＊＊6'会报错

该计算器思路：
1、没用使用递归，先找出并计算所有括号里的公式，再计算乘除和加减
2、所有的数字都认为是浮点型操作，以此来保留小数
使用技术：
1、正则表达式
2、tkinter

流程图：





代码如下：

#!/usr/bin/env python3
#antuor:Alan

import  re
from functools import reduce
from tkinter import *

'''处理特殊－号运算'''
def minus_operation(expresstion):
minus_operators = re.split("-",expresstion)
calc_list = re.findall("[0-9]",expresstion)
if minus_operators[0] =="":
calc_list[0] = '-%s' % calc_list[0]
res = reduce(lambda x,y:float(x)-float(y),calc_list)
print(">>>>>>>>>>>>>>减号[%s]运算结果:" % expresstion,res)
return res

'''reduce()对sequence连续使用function, 如果不给出initial, 则第一次调用传递sequence的两个元素,
以后把前一次调用的结果和sequence的下一个元素传递给function'''

'''处理双运算符号'''
def del_duplicates(expresstion):
expresstion = expresstion.replace("++","+")
expresstion = expresstion.replace("--","-")
expresstion = expresstion.replace("+-","-")
expresstion = expresstion.replace("--","+")
expresstion = expresstion.replace('- -',"+")
e
return expresstion

'''＊／运算函数'''
def mutiply_dividend(expresstion):
calc_list = re.split("[*/]",expresstion)         #用＊ or /分割公式
operators = re.findall("[*/]",expresstion)       #找出所有＊和／号
res = None
for index,i in enumerate(calc_list):
if res:
if operators[index-1] =='*':
res *= float(i)
elif operators[index-1] =='/':
res /=float(i)
else :
res = float(i)
procession0 = "[%s]运算结果=" % expresstion,res
final_result.insert(END,procession0)        #插入窗体
print(procession0)
return res

'''处理运算符号顺序混乱情况'''
def special_features(plus_and_minus_operators,multiply_and_dividend):

for index,i  in enumerate(multiply_and_dividend):
i = i.strip()
if i.endswith("*") or i.endswith("/"):
multiply_and_dividend[index] = multiply_and_dividend[index] + plus_and_minus_operators[index] + multiply_and_dividend[index+1]
del multiply_and_dividend[index+1]
del plus_and_minus_operators[index]
return plus_and_minus_operators,multiply_and_dividend

def minus_special(operator_list,calc_list):
for index,i in enumerate(calc_list):
if i =='':
calc_list[index+1] = i + calc_list[index+1].strip()

'''运算除了（）的公式＋－＊／'''
def figure_up(expresstion):
expresstion = expresstion.strip("()")       #去掉外面括号
expresstion = del_duplicates(expresstion)   #去掉重复＋－号
plus_and_minus_operators = re.findall("[+-]",expresstion)
multiply_and_dividend = re.split("[+-]",expresstion)
if len(multiply_and_dividend[0].strip()) ==0:
multiply_and_dividend[1] = plus_and_minus_operators[0] + multiply_and_dividend[1]
del multiply_and_dividend[0]
del plus_and_minus_operators[0]

plus_and_minus_operators,multiply_and_dividend = special_features(plus_and_minus_operators,multiply_and_dividend)
for index,i in enumerate(multiply_and_dividend):
if re.search("[*/]",i):
sub_res = mutiply_dividend(i)
multiply_and_dividend[index] = sub_res

print(multiply_and_dividend,plus_and_minus_operators)    #计算
final_res = None
for index,item in enumerate(multiply_and_dividend):
if final_res:
if plus_and_minus_operators[index-1] == '+':
final_res += float(item)
elif plus_and_minus_operators[index-1] == '-':
final_res -= float(item)
else:
final_res = float(item)
procession = '[%s]计算结果:' % expresstion,final_res
final_result.insert(END,procession)        #插入窗体
print(procession)
return final_res

"""主函数：运算逻辑：先计算拓号里的值,算出来后再算乘除,再算加减"""
def calculate():
expresstion = expresstions.get()                  #获取输入框值
flage = True
calculate_res = None                              #初始化计算结果为None
while flage:
m = re.search("\([^()]*\)",expresstion)       #先找最里层的（）
# pattern = re.compile(r"\([^()]*\)")
# m = pattern.match(expresstion)
if m:
sub_res = figure_up(m.group())            #运算（）里的公式
expresstion = expresstion.replace(m.group(),str(sub_res))    #运算完毕把结果替换掉公式
else:
print('---------------括号已经计算完毕--------------')
procession1 = "最终计算结果:",figure_up(expresstion)
final_result.insert(END,procession1)      #插入窗体
print('\033[31m最终计算结果:',figure_up(expresstion))

flage = False

if __name__=="__main__":
# res = calculate("1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )")
window = Tk()                 ###创建窗体
window.title('计算器')        ###命名窗体
frame1 = Frame(window)       ###框架1
frame1.pack()                ###放置
frame2 = Frame(window)       ###框架2
frame2.pack()                ###放置
lable = Label(frame1,text = "请输入公式：")   ###文字标签
lable.pack()
expresstions = StringVar()    ###输入框属性，字符串
entryname = Entry(frame1,textvariable = expresstions)  ###文本输入框
bt_get_expresstions = Button(frame1,text = "提交",command = calculate)  ###按钮挂件
bt_get_expresstions.pack()
entryname.pack()
lable.grid(row =1,column =1)    ###位置
entryname.grid(row=1,column =2)
bt_get_expresstions.grid(row =1,column =3)
final_result = Text(frame2)    ###计算结果显示框
final_result.tag_config("here", background="yellow", foreground="blue")
final_result.pack()
window.mainloop()             ###事件循环