self.__symbol = 0
def __setattr(self, name, value):
if name == "denominator" and value == 0:
raise ZeroDenominatorError("denominator by zero")
return super().__setattr(self, name, value)
# -self
def __neg__(self):
a, b = self.numerator, self.denominator
if self.__symbol:
return Fraction(a, b)
return Fraction(abs(a), abs(b))
# +self
def __pos__(self):
return self
def __str__(self):
a, b = self.numerator, self.denominator
if a == 0:
return "0"
return "-" * abs(self.__symbol - 1) + f"{abs(a)}/{abs(b)}"
def __repr__(self):
__repr__ == __str__
def __add__(self, other):
a, b = self.numerator, self.denominator
c, d = other.numerator, other.denominator
if a == 0:
return Fraction(c, d)
if c == 0:
return Fraction(a, b)
ad = a * d
bc = b * c
bd = b * d
return Fraction(ad + bc, bd)
def __sub__(self, other):
a, b = self.numerator, self.denominator
c, d = other.numerator, other.denominator
if a == 0:
return -Fraction(c, d)
if c == 0:
return Fraction(a, b)
ad = a * d
bc = b * c
bd = b * d
return Fraction(ad + bc, bd)
def __mul__(self, other):
return Fraction(
self.numerator * other.numerator, self.denominator * other.denominator
def __truediv__(self, other):
if other.numerator == 0:
raise ZeroDivisionError("division by zero")
ad, bc = self.numerator * other.denominator, self.denominator * other.numerator
return Fraction(ad, bc)
# int(self)
def __int__(self):
return int(self.numerator / self.denominator)
# float(self)
def __float__(self):
return self.numerator / self.denominator
# !=
def __ne__(self, other) -> bool:
if isinstance(other, Fraction):
return str(self) != str(other)
return True
def __eq__(self, other):
if isinstance(other, Fraction):
return str(self) == str(other)
return False
def __lt__(self, other) -> bool:
if isinstance(other, Fraction):
return float(self) < float(other)
raise TypeError(
def __le__(self, other) -> bool:
if isinstance(other, Fraction):
return float(self) <= float(other)
raise TypeError(
f"'<=' not supported between instances of 'Fraction' and {type(other)}"
def __gt__(self, other) -> bool:
if isinstance(other, Fraction):
return float(self) > float(other)
raise TypeError(
f"'>' not supported between instances of 'Fraction' and {type(other)}"
def __ge__(self, other) -> bool:
if isinstance(other, Fraction):
return float(self) >= float(other)
raise TypeError(
f"'>=' not supported between instances of 'Fraction' and {type(other)}"
# abs(self)
def __abs__(self):
a, b = self.numerator, self.denominator
if self.__symbol:
return Fraction(a, b)
return Fraction(-a, b)
# bool(self)
def __bool__(self):
if self.numerator == 0:
return False
return True
mysql客户端能创建schema的用户吗 mysql建立用户
今天搭建一个测试环境时，遇到了一个很隐蔽的问题。有必要分享一下 | user | password | host |
+------+-------------------------------------------+--------------------+
| root | *81F5E21E
