python 的 sum() 和非整数值
问题描述
有没有一种简单快捷的方法来使用非整数值的 sum()?
Is there a simple and quick way to use sum() with non-integer values?
所以我可以这样使用它:
So I can use it like this:
class Foo(object):
def __init__(self,bar)
self.bar=bar
mylist=[Foo(3),Foo(34),Foo(63),200]
result=sum(mylist) # result should be 300
我尝试覆盖 __add__
和 __int__
等,但我还没有找到解决方案
I tried overriding __add__
and __int__
etc, but I don't have found a solution yet
解决办法是实现:
def __radd__(self, other):
return other + self.bar
正如威尔在他的帖子中所建议的那样.但一如既往,条条大路通罗马,但我认为这是最好的解决方案,因为我的课堂不需要 __add__
as Will suggested in his post. But as always, all roads lead to Rome, but I think this is the best solution since I don't need __add__
in my class
解决方案
这有点棘手 - sum() 函数获取开始并将其添加到下一个等等
Its a bit tricky - the sum() function takes the start and adds it to the next and so on
你需要实现 __radd__
方法:
class T:
def __init__(self,x):
self.x = x
def __radd__(self, other):
return other + self.x
test = (T(1),T(2),T(3),200)
print sum(test)
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