Python之字符串计算（计算器）

Python之字符串计算（计算器）
import re expression =
'-1-2*((60+2*(-3-40.0+42425/5)*(9-2*5/3+357/553/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))+56+(56-45)'
question = eval(expression) print(question) def arithmetic(expression='1+1'): #
content = re.search('\(([\-\+\*\/]*\d+\.?\d*)+\)', expression) # (-3-40.0/5)
content = re.search('\(([-+*/]*\d+\.?\d*)+\)', expression) # (-3-40.0/5)
print(111, content) if content: content = content.group() content =
content[1:-1] print('content:', content) replace_content =
next_arithmetic(content) expression = re.sub('\(([-+*/]*\d+\.?\d*)+\)',
replace_content, expression, count=1) print('next_expression:', expression)
else: answer = next_arithmetic(expression) return answer return
arithmetic(expression) def next_arithmetic(content): while True:
next_content_mul_div = re.search('\d+\.?\d*[*/][-+]?\d+\.?\d*', content) #
找出带有*/的式子 if next_content_mul_div: # 如果content含有带有*/的式子 next_content_mul_div =
next_content_mul_div.group() print('next_content_mul_div:',
next_content_mul_div) mul_div_content = mul_div(next_content_mul_div) #
计算出带有*/的式子 print('mul_div_content:', mul_div_content) content =
re.sub('\d+\.?\d*[*/][-+]?\d+\.?\d*', str(mul_div_content), content, count=1) #
把带有*/的式子计算出来后替换掉 print('content:', content) continue next_content_add_sub =
re.search('-?\d+\.?\d*[-+][-+]?\d+\.?\d*', content) # 找出带有-+的式子 if
next_content_add_sub: # 如果content含有带有+-的式子 next_content_add_sub =
next_content_add_sub.group() print('next_content_add_sub:',
next_content_add_sub) add_sub_content = add_sub(next_content_add_sub) #
计算出带有-+的式子 print('add_sub_content:', add_sub_content) add_sub_content =
str(add_sub_content) content = re.sub('-?\d+\.?\d*[-+]-?\d+\.?\d*',
str(add_sub_content), content, count=1) # 把带有-+的式子计算出来后替换掉 print('content:',
content) continue else: break return content def add_sub(content): if '+' in
content: content = content.split('+') print(content) content =
float(content[0]) + float(content[1]) return content elif '-' in content:
content = content.split('-') # 减法情况有多种 if content[0] == '-' and content[2] ==
'-': # content = content.split('-') print(content) content = -float(content[1])
- float(content[-1]) return content if content[0] == '-': # content =
content.split('-') print(content) content = -float(content[1]) -
float(content[-1]) return content if content[1] == '-' and content[2] == '-': #
content = content.split('-') print(content) content = -float(content[0]) +
float(content[-1]) return content if content[1] == '': # content =
content.split('-') print(content) content = float(content[0]) -
float(content[2]) return content if content[0] == '' and content[2] != '':
print(content) content = -float(content[1]) - float(content[2]) return content
if content[0] == '' and content[2] == '': print(content) content =
-float(content[1]) + float(content[3]) return content else: # content =
content.split('-') print(content) content = float(content[0]) -
float(content[1]) return content def mul_div(content): if '*' in content:
content = content.split('*') print(content) content = float(content[0]) *
float(content[1]) return content elif '/' in content: content =
content.split('/') print(content) content = float(content[0]) /
float(content[1]) return content # expression =
'1-2*((60+2*(-3-40.0/5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))'
expression =
'-1-2*((60+2*(-3-40.0+42425/5)*(9-2*5/3+357/553/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))+56+(56-45)'
answer = arithmetic(expression) print(answer)

• « 上一篇：浅谈ASP.NET Core中IOC与DI的理解和使用
• » 下一篇：抖音海外版tiktok404 & 简洁国际版apk