1 #!usr/bin/evn python

2 #coding:cp936

3 #Author:Siwen

4

5

6 print ("Hello world!")7

8

9 importre10

11 defhandle_special_occactions(plus_minus,multiply_and_dividend):12 #有时会出现这种情况 , ['-', '-'] ['1 ', ' 2 * ', '14969036.7968254'],2*...后面这段实际是 2*-14969036.7968254,需要特别处理下,太恶心了'''

13 for index,i inenumerate(multiply_and_dividend):14 i =i.strip()15 if i.endswith("*") or i.endswith("/"):16 multiply_and_dividend[index] = multiply_and_dividend[index] + plus_minus[index] + multiply_and_dividend[index+1]17 del multiply_and_dividend[index+1]18 delplus_minus[index]19 returnplus_minus,multiply_and_dividend20

21 defremove_jia(formula):22 formula = formula.replace("++","+")23 formula = formula.replace("+-","-")24 formula = formula.replace("-+","-")25 formula = formula.replace("--","+")26 formula = formula.replace("- -","+")27 returnformula28

29

30 defcompute_mutiply_and_dividend(formula):31 operators = re.findall("[*/]", formula )32 calc_list = re.split("[*/]", formula )33 t_res =None34 for index,item inenumerate(calc_list):35 item=item.strip()36 if t_res: #代表不是第一次循环

37 if operators[index-1] == '/':38 t_res /=float(item)39 if operators[index-1] == '*':40 t_res *=float(item)41 else:42 t_res =float(item)43 print("乘除结果为：",t_res)44 return(t_res)45

46 defcompute(formula):47 #计算不带括号的算式

48 formula=formula.strip('()')49 formula=remove_jia(formula)50 plus_minus=re.findall(r'[+-]',formula)51 multiply_and_dividend = re.split("[+-]", formula)#去除乘除的公式

52 if len(multiply_and_dividend[0].strip()) == 0:#代表这肯定是个负号

53 multiply_and_dividend[1] = plus_minus[0] + multiply_and_dividend[1]54 delmultiply_and_dividend[0]55 delplus_minus[0]56

57 plus_minus,multiply_and_dividend=handle_special_occactions(plus_minus,multiply_and_dividend)58

59 for index,i inenumerate(multiply_and_dividend):60 if re.search("[*/]",i):61 sub_res =compute_mutiply_and_dividend(i)62 multiply_and_dividend[index] =sub_res63

64 print(multiply_and_dividend, plus_minus)65 total_res =None66 for index,item inenumerate(multiply_and_dividend):67

68 if total_res: #代表不是第一次循环

69

70 if plus_minus[index-1] == '+':71 total_res +=float(item)72 if plus_minus[index-1] == '-':73 total_res -=float(item)74

75 else:76 total_res =float(item)77 print('算式%s计算结果为：'%formula,total_res)78 return(total_res)79

80

81

82 defcale(formula):83 #主要逻辑，先算括号里的值，再算乘除，再算加减

84 parenthesise_flag=True85 sub=None86 sub_res=087 whileparenthesise_flag:88 m=re.search('\([^()]*\)',formula)89

90 ifm:91 m=m.group()92 print(m)93 #print('先算括号里'，m)

94 sub_res=compute(m)95 print(sub_res)96 formula=formula.replace(m,str(sub_res))97 else:98 print('没有括号了')99 #formula=formula.replace(m.group(),str(sub_res))

100 print(formula)101 sub=compute(formula)102 #print '计算结果为：'，sub

103 parenthesise_flag=False#算式中的括号都已经被剥除了

104 res="1-2*((60-30+(-40/5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))"

105 #res='1+2*(3+4)'

106 res=cale(res)107

108