团队科学计算器-模块开发过程

• 项目托管平台地址：https://gitee.com/Marly/codes/vbnfqyx3mzpsk8062rc9e77
  fun功能,实现了不含括号的表达式计算 实现的过程：

  def fun(s):
  l = re.findall('([\d\.]+|/|-|\+|\*)',s)
  sum=0
  while 1:
  if '*' in l and '/' not in l:
  md(l, '*')
  elif '*' not in l and '/' in l:
  md(l, '/')
  elif '*' in l and '/' in l:
  a = l.index('*')
  b = l.index('/')
  if a < b:
  md(l, '*')
  else:
  md(l, '/')
  else:
  if l[0]=='-':
  l[0]=l[0]+l[1]
  del l[1]
  sum += float(l[0])
  for i in range(1, len(l), 2):
  if l[i] == '+' and l[i + 1] != '-':
  sum += float(l[i + 1])
  elif l[i] == '+' and l[i + 1] == '-':
  sum -= float(l[i + 2])
  elif l[i] == '-' and l[i + 1] == '-':
  sum += float(l[i + 2])
  elif l[i] == '-' and l[i + 1] != '-':
  sum -= float(l[i + 1])
  break
  return sum

  calculate功能,:实现了带有括号的递归运算。实现过程是

• def calculate(expression):
  ex=[]
  ans=0
  if '(' not in expression:
  ans=fun(expression)
  return ans
  for i in range(len(expression)):
  if expression[i]=='(':
  ex.append(i)
  elif expression[i]==')':
  temp=0
  sub=expression[ex[len(ex)-1]+1:i]
  temp=fun(sub)
  expression=expression[0:ex[len(ex)-1]]+str(temp)+expression[i+1:len(expression)+1]
  ex.pop()