comefrom: <doocs>0227.Basic Calculator II_1.py
code: def calculate( s: str) -> int:
      num, n = 0, len(s)
      pre_sign = '+'
      stack = []
      for i in range(n):
          if s[i].isdigit():
              num = num * 10 + int(s[i])
          if i == n - 1 or (not s[i].isdigit() and s[i] != ' '):
              if pre_sign == '+':
                  stack.append(num)
              elif pre_sign == '-':
                  stack.append(-num)
              elif pre_sign == '*':
                  stack.append(stack.pop() * num)
              else:
                  stack.append(int(stack.pop() / num))
              pre_sign = s[i]
              num = 0
      res = 0
      while stack:
          res += stack.pop()
      return res
masked: def sample_funcname ( var_0 : str ) -> int :
      var_4 , var_6 = 0 , len ( var_0 )
      var_8 = '+'
      var_9 = [ ]
      for var_11 in range ( var_6 ) :
          if var_0 [ var_11 ].isdigit ( ) :
              var_4 = var_4 * 10 + int ( var_0 [ var_11 ] )
          if var_11 == var_6 - 1 or ( not var_0 [ var_11 ].isdigit ( ) and var_0 [ var_11 ] != ' ' ) :
              if var_8 == '+' :
                  var_9.append ( var_4 )
              elif var_8 == '-' :
                  var_9.append ( - var_4 )
              elif var_8 == '*' :
                  var_9.append ( var_9.pop ( ) * var_4 )
              else :
                  var_9.append ( int ( var_9.pop ( ) / var_4 ) )
              var_8 = var_0 [ var_11 ]
              var_4 = 0
      var_20 = 0
      while var_9 :
          var_20 += var_9.pop ( )
      return var_20
  