3.3.7 模拟数值类型 Emulating numeric types

The following methods can be defined to emulate numeric objects. Methods corresponding to operations that are not supported by the particular kind of number implemented (e.g., bitwise operations for non-integral numbers) should be left undefined.

以下方法用于模拟数值类型.其中,对于有些种类数值所不支持的操作对应的方法未定义(如, 对非整数值的位运算).

__add__( self, other)
__sub__( self, other)
__mul__( self, other)
__floordiv__( self, other)
__mod__( self, other)
__divmod__( self, other)
__pow__( self, other[, modulo])
__lshift__( self, other)
__rshift__( self, other)
__and__( self, other)
__xor__( self, other)
__or__( self, other): These methods are called to implement the binary arithmetic operations (+, -, *, //, %, divmod(), pow(), **, <<, >>, &, ^, |). For instance, to evaluate the expression x+y, where x is an instance of a class that has an __add__() method, x.__add__(y) is called. The __divmod__() method should be the equivalent to using __floordiv__() and __mod__(); it should not be related to __truediv__() (described below). Note that __pow__() should be defined to accept an optional third argument if the ternary version of the built-in pow() function is to be supported.
这些方法用于实现二元算术运算(+,-,*,/,

__div__( self, other)
__truediv__( self, other): The division operator (/) is implemented by these methods. The __truediv__() method is used when __future__.division is in effect, otherwise __div__() is used. If only one of these two methods is defined, the object will not support division in the alternate context; TypeError will be raised instead.
这些方法用于支持除法运算符. __truediv__()方法在__future__.division有效时使用,否则就使用__div__(), 如果只定义了其中一个方法, 那么这个对象在哪种情况下都是不支持除法运算的,此时会有一个TypeError异常抛出.

__radd__( self, other)
__rsub__( self, other)
__rmul__( self, other)
__rdiv__( self, other)
__rtruediv__( self, other)
__rfloordiv__( self, other)
__rmod__( self, other)
__rdivmod__( self, other)
__rpow__( self, other)
__rlshift__( self, other)
__rrshift__( self, other)
__rand__( self, other)
__rxor__( self, other)
__ror__( self, other): These methods are called to implement the binary arithmetic operations (+, -, *, /, %, divmod(), pow(), **, <<, >>, &, ^, |) with reflected (swapped) operands. These functions are only called if the left operand does not support the corresponding operation. For instance, to evaluate the expression x-y, where y is an instance of a class that has an __rsub__() method, y.__rsub__(x) is called. Note that ternary pow() will not try calling __rpow__() (the coercion rules would become too complicated).
这些方法用于实现二元算术运算(+,-,*,/,

__iadd__( self, other)
__isub__( self, other)
__imul__( self, other)
__idiv__( self, other)
__itruediv__( self, other)
__ifloordiv__( self, other)
__imod__( self, other)
__ipow__( self, other[, modulo])
__ilshift__( self, other)
__irshift__( self, other)
__iand__( self, other)
__ixor__( self, other)
__ior__( self, other): These methods are called to implement the augmented arithmetic operations (+=, -=, *=, /=, %=, **=, <<=, >>=, &=, ^=, |=). These methods should attempt to do the operation in-place (modifying self) and return the result (which could be, but does not have to be, self). If a specific method is not defined, the augmented operation falls back to the normal methods. For instance, to evaluate the expression x+=y, where x is an instance of a class that has an __iadd__() method, x.__iadd__(y) is called. If x is an instance of a class that does not define a __iadd() method, x.__add__(y) and y.__radd__(x) are considered, as with the evaluation of x+y.
这些方法用于实现赋值运算符(+=, -=,*=,/=,

__neg__( self)
__pos__( self)
__abs__( self)
__invert__( self): Called to implement the unary arithmetic operations (-, +, abs() and ~).
实现一元运算符(-,+,abs(), )

__complex__( self)
__int__( self)
__long__( self)
__float__( self): Called to implement the built-in functions complex(), int(), long(), and float(). Should return a value of the appropriate type.
在自定义类上实现内建函数complex(), int(), long()和float()的功能, 应该返回适当的类型.

__oct__( self)
__hex__( self): Called to implement the built-in functions oct() and hex(). Should return a string value.
在自定义类上实现内建函数oct()和hex()的功能, 应该返回适当的串值.

__coerce__( self, other): Called to implement ``mixed-mode'' numeric arithmetic. Should either return a 2-tuple containing self and other converted to a common numeric type, or None if conversion is impossible. When the common type would be the type of other, it is sufficient to return None, since the interpreter will also ask the other object to attempt a coercion (but sometimes, if the implementation of the other type cannot be changed, it is useful to do the conversion to the other type here). A return value of NotImplemented is equivalent to returning None.
实现混合式数值运算, 返回值要么是一个包括已经转换到一般数值类型的数据的self和other的二元组,或者当转换无效时返回None. 当转换后的类型可能是其它类型时, 可以返回None, 因为解释器会试着强制地转换为其它类型(但有的情况下,如果其它的类型的实现不能改变, 那么就应该在这将其转换为该类型).