要求：
- 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(不能调用eval等类似功能偷懒实现)，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
1 import re
2
3 def main():
4
5 a = ''.join(input('请输入需要计算的算式').split())
6
7 while True:
8 if '(' in a:
9 ct = re.search(r'\(([^()]+)\)', a)
10 if ct is not None:
11 b = ct.groups()[0]
12 c = count(b)
13 a = re.sub(r'\(([^()]+)\)', str(c), a, 1)
14 else:
15 c = count(a)
16 print(c)
17 break
18
19 def add_min(a):
20 '''
21 计算加减法
22 :param:
23 :return:
24 '''
25
26 if '--' in a:
27 a = a.replace('--', '+')
28
29 c = re.findall(r'-?\d+\.?\d*', a)
30 ls = []
31 for i in c:
32 ls.append(float(i))
33 rest = sum(ls)
34 return rest
35
36
37 def mul(a):
38 '''
39 计算剩数
40 :param ct:
41 :return:
42 '''
43
44
45 b = re.search(r'\d+\.?\d*(\*-?\d+\.?\d*)+', a)
46 if b is not None:
47 b = b.group()
48 rest = 1
49 c = re.findall(r'-?\d+\.?\d*', b)
50 ls =[]
51 for item in c:
52 ls.append(float(item))
53 for i1 in range(len(ls)):
54 rest = rest * ls[i1]
55 a = re.sub(r'\d+\.?\d*(\*-?\d+\.?\d*)+', str(rest), a, 1)
56 return a
57
58
59
60 def div(a):
61 '''
62 计算出发
63 :param a:
64 :return:
65 '''
66
67 b = re.search(r'\d+\.?\d*(\/-?\d+\.?\d*)+', a)
68 if b is not None:
69 b = b.group()
70 c = re.findall(r'-?\d+\.?\d*', b)
71 ls =[]
72 for i in c:
73 ls.append(float(i))
74 rest = ls[0]
75 for i1 in range(1,len(ls)):
76 rest = rest / ls[i1]
77 a = re.sub(r'\d+\.?\d*(\/-?\d+\.?\d*)+', str(rest), a, 1)
78 return a
79
80
81 def count(b):
82 '''
83 计算结果
84 :return:
85 '''
86 while True:
87 if '*' in b:
88 c = b.split('*')
89 if '/' in c[0]:
90 b = div(b)
91 else:
92 b = mul(b)
93 elif '/' in b:
94 b = div(b)
95
96 elif '+' or '-' in b:
97 b = add_min(b)
98 return b
99 else:
100 return b
101
102
103
104
105 main()