python正則表達(dá)式之作業(yè)計(jì)算器
作業(yè):計(jì)算器開發(fā)
實(shí)現(xiàn)加減乘除及拓號(hào)優(yōu)先級(jí)解析
用戶輸入 1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )等類似公式后,必須自己解析里面的(),+,-,*,/符號(hào)和公式,運(yùn)算后得出結(jié)果,結(jié)果必須與真實(shí)的計(jì)算器所得出的結(jié)果一致
一、說明:
有一點(diǎn)bug就是不能計(jì)算冪次方,如:'6**6'會(huì)報(bào)錯(cuò)
該計(jì)算器思路:
1、沒用使用遞歸,先找出并計(jì)算所有括號(hào)里的公式,再計(jì)算乘除和加減
2、所有的數(shù)字都認(rèn)為是浮點(diǎn)型操作,以此來保留小數(shù)
使用技術(shù):
1、正則表達(dá)式
2、tkinter
二、流程圖:
三、代碼如下:
#!/usr/bin/env python3 #antuor:Alan import re from functools import reduce from tkinter import * '''處理特殊-號(hào)運(yùn)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(">>>>>>>>>>>>>>減號(hào)[%s]運(yùn)算結(jié)果:" % expresstion,res) return res '''reduce()對(duì)sequence連續(xù)使用function, 如果不給出initial, 則第一次調(diào)用傳遞sequence的兩個(gè)元素, 以后把前一次調(diào)用的結(jié)果和sequence的下一個(gè)元素傳遞給function''' '''處理雙運(yùn)算符號(hào)''' def del_duplicates(expresstion): expresstion = expresstion.replace("++","+") expresstion = expresstion.replace("--","-") expresstion = expresstion.replace("+-","-") expresstion = expresstion.replace("--","+") expresstion = expresstion.replace('- -',"+") e return expresstion '''*/運(yùn)算函數(shù)''' def mutiply_dividend(expresstion): calc_list = re.split("[*/]",expresstion) #用* or /分割公式 operators = re.findall("[*/]",expresstion) #找出所有*和/號(hào) 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]運(yùn)算結(jié)果=" % expresstion,res final_result.insert(END,procession0) #插入窗體 print(procession0) return res '''處理運(yùn)算符號(hào)順序混亂情況''' 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() '''運(yùn)算除了()的公式+-*/''' def figure_up(expresstion): expresstion = expresstion.strip("()") #去掉外面括號(hào) expresstion = del_duplicates(expresstion) #去掉重復(fù)+-號(hào) 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) #計(jì)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]計(jì)算結(jié)果:' % expresstion,final_res final_result.insert(END,procession) #插入窗體 print(procession) return final_res """主函數(shù):運(yùn)算邏輯:先計(jì)算拓號(hào)里的值,算出來后再算乘除,再算加減""" def calculate(): expresstion = expresstions.get() #獲取輸入框值 flage = True calculate_res = None #初始化計(jì)算結(jié)果為None while flage: m = re.search("\([^()]*\)",expresstion) #先找最里層的() # pattern = re.compile(r"\([^()]*\)") # m = pattern.match(expresstion) if m: sub_res = figure_up(m.group()) #運(yùn)算()里的公式 expresstion = expresstion.replace(m.group(),str(sub_res)) #運(yùn)算完畢把結(jié)果替換掉公式 else: print('---------------括號(hào)已經(jīng)計(jì)算完畢--------------') procession1 = "最終計(jì)算結(jié)果:",figure_up(expresstion) final_result.insert(END,procession1) #插入窗體 print('\033[31m最終計(jì)算結(jié)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() ###創(chuàng)建窗體 window.title('計(jì)算器') ###命名窗體 frame1 = Frame(window) ###框架1 frame1.pack() ###放置 frame2 = Frame(window) ###框架2 frame2.pack() ###放置 lable = Label(frame1,text = "請(qǐng)輸入公式:") ###文字標(biāo)簽 lable.pack() expresstions = StringVar() ###輸入框?qū)傩?,字符? entryname = Entry(frame1,textvariable = expresstions) ###文本輸入框 bt_get_expresstions = Button(frame1,text = "提交",command = calculate) ###按鈕掛件 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) ###計(jì)算結(jié)果顯示框 final_result.tag_config("here", background="yellow", foreground="blue") final_result.pack() window.mainloop() ###事件循環(huán)
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