Python3 操作符重载方法

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原文: http://blog.csdn.net/Rozol/article/details/70769628
#coding=utf-8

# specialfuns.py 操作符重载方法

# 类(class)通过使用特殊名称的方法(__len__(self))来实现被特殊语法(len())的调用

# 构造 与 析构 方法

class demo1:

    # 构造方法, 对象实例化时调用

    def __init__(self):

        print("构造方法")

    # 析构方法, 对象被回收时调用

    def __del__(self):

        print("析构方法")

# new

class demo2(object):

    # __init__之前调用, 一般用于重写父类的__new__方法, 具体使用见 类 文章的 元类 代码部分(http://blog.csdn.net/rozol/article/details/69317339)

    def __new__(cls):

        print("new")

        return object.__new__(cls)

# 算术运算

class demo3:

    def __init__(self, num):

        self.data = num

    # +

    def __add__(self, other):

        return self.data + other.data

    # -

    def __sub__(self, other):

        return self.data - other.data

    # *

    def __mul__(self, other):

        return self.data * other.data

    # /

    def __truediv__(self, other):

        return self.data / other.data

    # //

    def __floordiv__(self, other):

        return self.data // other.data

    # %

    def __mod__(self, other):

        return self.data % other.data

    # divmod()

    def __divmod__(self, other):

        # 商(10/5),余数(10%5)

        return self.data / other.data, self.data % other.data

    # **

    def __pow__(self, other):

        return self.data ** other.data

    # <<

    def __lshift__(self, other):

        return self.data << other.data

    # >>

    def __rshift__(self, other):

        return self.data >> other.data

    # &

    def __and__(self, other):

        return self.data & other.data

    # ^

    def __xor__(self, other):

        return self.data ^ other.data

    # |

    def __or__(self, other):

        return self.data | other.data

class none:

    def __init__(self, num):

        self.data = num

# 反算术运算符(a+b, 若a不支持算术运算符,则寻找b的算术运算符)(注:位置变换, 在原始函数名前+r)

class demo4:

    def __init__(self, num):

        self.data = num

    # +

    def __radd__(self, other):

        return other.data + self.data

    # -

    def __rsub__(self, other):

        return other.data - self.data

    # *

    def __rmul__(self, other):

        return other.data * self.data

    # /

    def __rtruediv__(self, other):

        return other.data / self.data

    # //

    def __rfloordiv__(self, other):

        return other.data // self.data

    # %

    def __rmod__(self, other):

        return other.data % self.data

    # divmod()

    def __rdivmod__(self, other):

        return other.data / self.data, other.data % self.data

    # **

    def __rpow__(self, other):

        return other.data ** self.data

    # <<

    def __rlshift__(self, other):

        return other.data << self.data

    # >>

    def __rrshift__(self, other):

        return other.data >> self.data

    # &

    def __rand__(self, other):

        return other.data & self.data

    # ^

    def __rxor__(self, other):

        return other.data ^ self.data

    # |

    def __ror__(self, other):

        return other.data | self.data

# 增量赋值运算,(注:位置同原始函数,在原始函数名前+i)

class demo5():

    def __init__(self, num):

        self.data = num

    # +=

    def __iadd__(self, other):

        return self.data + other

    # -=

    def __isub__(self, other):

        return self.data - other

    # *=

    def __imul__(self, other):

        return self.data * other

    # /=

    def __itruediv__(self, other):

        return self.data / other

    # //=

    def __ifloordiv__(self, other):

        return self.data // other

    # %=

    def __imod__(self, other):

        return self.data % other

    # **=

    def __ipow__(self, other):

        return self.data ** other

    # <<=

    def __ilshift__(self, other):

        return self.data << other

    # >>=

    def __irshift__(self, other):

        return self.data >> other

    # &=

    def __iand__(self, other):

        return self.data & other

    # ^=

    def __ixor__(self, other):

        return self.data ^ other

    # |=

    def __ior__(self, other):

        return self.data | other

# 比较运算符

class demo6:

    def __init__(self, num):

        self.data = num

    # <

    def __lt__(self, other):

        return self.data < other.data

    # <=

    def __le__(self, other):

        return self.data <= other.data

    # ==

    def __eq__(self, other):

        return self.data == other.data

    # !=

    def __ne__(self, other):

        return self.data != other.data

    # >

    def __gt__(self, other):

        return self.data > other.data

    # >=

    def __ge__(self, other):

        return self.data >= other.data

# 一元操作符

class demo7:

    def __init__(self, num):

        self.data = num

    # + 正号

    def __pos__(self):

        return +abs(self.data)

    # - 负号

    def __neg__(self):

        return -abs(self.data)

    # abs() 绝对值

    def __abs__(self):

        return abs(self.data)

    # ~ 按位取反

    def __invert__(self):

        return ~self.data

    # complex() 字符转数字

    def __complex__(self):

        return 1+2j

    # int() 转为整数

    def __int__(self):

        return 123

    # float() 转为浮点数

    def __float__(self):

        return 1.23

    # round()  近似值

    def __round__(self):

        return 1.123

# 格式化

class demo8:

    # print() 打印

    def __str__(self):

        return "This is the demo."

    # repr() 对象字符串表示

    def __repr__(self):

        return "This is a demo."

    # bytes() 对象字节字符串表现形式

    def __bytes__(self):

        return b"This is one demo."

    # format() 格式化

    def __format__(self, format_spec):

        return self.__str__()

# 属性访问

class demo9:

    # 获取(不存在)属性

    def __getattr__(self):

        print ("访问的属性不存在")

    # getattr() hasattr() 获取属性

    def __getattribute__(self, attr):

        print ("访问的属性是%s"%attr)

        return attr

    # setattr() 设置属性

    def __setattr__(self, attr, value):

        print ("设置 %s 属性值为 %s"%(attr, value))

    # delattr() 删除属性

    def __delattr__(self, attr):

        print ("删除 %s 属性"%attr)

# ===================================================================

# 描述器(类(test1)的实例出现在属主类(runtest)中,这些方法才会调用)(注:函数调用,这些方法不会被调用)

class test1:

    def __init__(self, value = 1):

        self.value = value * 2

    def __set__(self, instance, value):

        print("set %s %s %s"%(self, instance, value))

        self.value = value * 2

    def __get__(self, instance, owner):

        print("get %s %s %s"%(self, instance, owner))

        return self.value

    def __delete__(self, instance):

        print("delete %s %s"%(self, instance))

        del self.value

class test2:

    def __init__(self, value = 1):

        self.value = value + 0.3

    def __set__(self, instance, value):

        print("set %s %s %s"%(self, instance, value))

        instance.t1 = value + 0.3

    def __get__(self, instance, owner):

        print("get %s %s %s"%(self, instance, owner))

        return instance.t1

    def __delete__(self, instance):

        print("delete %s %s"%(self, instance))

        del self.value

class runtest:

    t1 = test1()

    t2 = test2()

# ---

# 自定义property

class property_my:

    def __init__(self, fget=None, fset=None, fdel=None):

        self.fget = fget

        self.fset = fset

        self.fdel = fdel

    # 对象被获取(self自身, instance调用该对象的对象(demo9), owner调用该对象的对象类对象(demo9))

    def __get__(self, instance, owner):

        print("get %s %s %s"%(self, instance, owner))

        return self.fget(instance)

    # 对象被设置属性时

    def __set__(self, instance, value):

        print("set %s %s %s"%(self, instance, value))

        self.fset(instance, value)

    # 对象被删除时

    def __delete__(self, instance):

        print("delete %s %s"%(self, instance))

        self.fdel(instance)

class demo10:

    def __init__(self):

        self.num = None

    def setvalue(self, value):

        self.num = value

    def getvalue(self):

        return self.num

    def delete(self):

        del self.num

    x = property_my(getvalue, setvalue, delete)

# ===================================================================

# 自定义容器

class lis:

    def __init__(self, *args):

        self.lists = args

        self.size = len(args)

        self.startindex = 0

        self.endindex = self.size

    # len() 容器元素数量

    def __len__(self):

        return self.size;

    # lis[1] 获取元素

    def __getitem__(self, key = 0):

        return self.lists[key]

    # lis[1] = value 设置元素

    def __setitem__(self, key, value):

        pass

    # del lis[1] 删除元素

    def __delitem__(self, key):

        pass

    # 返回迭代器

    def __iter__(self):

        return self

    # rversed() 反向迭代器

    def __reversed__(self):

        while self.endindex > 0:

            self.endindex -= 1

            yield self[self.endindex]

    # next() 迭代器下个元素

    def __next__(self):

        if self.startindex >= self.size:

            raise StopIteration # 控制迭代器结束

        elem = self.lists[self.startindex]

        self.startindex += 1

        return elem

    # in / not in

    def __contains__(self, item):

        for i in self.lists:

            if i == item:

                return True

        return False

# yield 生成器(执行一次返回,下次继续执行后续代码返回)

def yielddemo():

    num = 0

    while 1: # 1 == True; 0 == False

        if num >= 10:

            raise StopIteration

        num += 1

        yield num

# 能接收数据的生成器

def yielddemo_1():

    while 1:

        num = yield

        print(num)

# with 自动上下文管理

class withdemo:

    def __init__(self, value):

        self.value = value

    # 返回值为 as 之后的值

    def __enter__(self):

        return self.value

    # 执行完成,退出时的数据清理动作

    def __exit__(self, exc_type, exc_value, traceback):

        del self.value

if __name__ == "__main__":

    # 构造与析构

    d1 = demo1()

    del d1

    # new

    d2 = demo2()

    # 算术运算符

    d3 = demo3(3)

    d3_1 = demo3(5)

    print(d3 + d3_1)

    print(d3 - d3_1)

    print(d3 * d3_1)

    print(d3 / d3_1)

    print(d3 // d3_1)

    print(d3 % d3_1)

    print(divmod(d3, d3_1))

    print(d3 ** d3_1)

    print(d3 << d3_1)

    print(d3 >> d3_1)

    print(d3 & d3_1)

    print(d3 ^ d3_1)

    print(d3 | d3_1)

    # 反运算符

    d4 = none(3)

    d4_1 = demo4(5)

    print(d4 + d4_1)

    print(d4 - d4_1)

    print(d4 * d4_1)

    print(d4 / d4_1)

    print(d4 // d4_1)

    print(d4 % d4_1)

    print(divmod(d4, d4_1))

    print(d4 ** d4_1)

    print(d4 << d4_1)

    print(d4 >> d4_1)

    print(d4 & d4_1)

    print(d4 ^ d4_1)

    print(d4 | d4_1)

    # 增量赋值运算(测试时注释其他代码)

    d5 = demo5(3)

    d5 <<= 5

    d5 >>= 5

    d5 &= 5

    d5 ^= 5

    d5 |= 5

    d5 += 5

    d5 -= 5

    d5 *= 5

    d5 /= 5

    d5 //= 5

    d5 %= 5

    d5 **= 5

    print(d5)

    # 比较运算符

    d6 = demo6(3)

    d6_1 = demo6(5)

    print(d6 < d6_1)

    print(d6 <= d6_1)

    print(d6 == d6_1)

    print(d6 != d6_1)

    print(d6 > d6_1)

    print(d6 >= d6_1)

    # 一元操作符(测试时注释其他代码)

    d7 = demo7(-5)

    num = +d7

    num = -d7

    num = abs(d7)

    num = ~d7

    print(num)

    print(complex(d7))

    print(int(d7))

    print(float(d7))

    print(round(d7))

    # 格式化

    d8 = demo8()

    print(d8)

    print(repr(d8))

    print(bytes(d8))

    print(format(d8, ""))

    # 属性访问

    d9 = demo9()

    setattr(d9, "a", 1) # => 设置 a 属性值为 1

    print(getattr(d9, "a")) # => a / 访问的属性是a

    print(hasattr(d9, "a")) # => True / 访问的属性是a

    delattr(d9, "a") # 删除 a 属性

    # ---

    d9.x = 100 # => 设置 x 属性值为 100

    print(d9.x) # => x / 访问的属性是x

    del d9.x # => 删除 x 属性

    # 描述器

    r = runtest()

    r.t1 = 100 # =>  <__main__.test1> <__main__.runtest> 100

    print(r.t1) # => 200 /  <__main__.test1> <__main__.runtest> <class '__main__.runtest'>

    del r.t1 # =>  <__main__.test1> <__main__.runtest>

    r.t2 = 200 # => <__main__.test2> <__main__.runtest> 200 / <__main__.test1> <__main__.runtest> 200.3

    print(r.t2) # => 400.6 / <__main__.test2> <__main__.runtest> <class '__main__.runtest'> /  <__main__.test1> <__main__.runtest> <class '__main__.runtest'>

    del r.t2 # <__main__.test2> <__main__.runtest>

    # ---

    # 自定义property

    d10 = demo10()

    d10.x = 100; # => <__main__.property_my> <__main__.demo10> 100

    print(d10.x) # => 100 / <__main__.property_my> <__main__.demo10> <class '__main__.demo10'>

    del d10.x # => <__main__.property_my> <__main__.demo10>

    d10.num = 200;

    print(d10.num) # => 200

    del d10.num

    # 自定义容器(迭代器Iterator)

    lis = lis(1,2,3,4,5,6)

    print(len(lis))

    print(lis[1])

    print(next(lis))

    print(next(lis))

    print(next(lis))

    for i in lis:

        print (i)

    for i in reversed(lis):

        print (i)

    print(3 in lis)

    print(7 in lis)

    print(3 not in lis)

    print(7 not in lis)

    # yield 生成器(可迭代对象Iterable)

    for i in yielddemo():

        print (i)

    # ---

    iters = iter(yielddemo())

    print(next(iters))

    print(next(iters))

    # --- 发送数据给生成器 ---

    iters = yielddemo_1()

    next(iters)

    iters.send(6) # 发送数据并执行

    iters.send(10)

    # with 自动上下文管理

    with withdemo("Less is more!") as s:

        print(s)
操作符重载方法

【转】Python3 操作符重载方法

Python3 操作符重载方法
