Python 对象的初始化函数及调用函数

# coding=utf-8

class DistanceFrom(object):
    def __init__(self,origin):
        self.origin=origin
    def __call__(self,x):
        return abs(x-self.origin)
    
nums=[1,7,6,4,3]  

k1=DistanceFrom(5) #__init__()初始化新建实例k1
k1(1)#=k1.__call__(1)
#4
nums.sort(key=k1)#key函数设为k1.call()对nums中各元素进行计算，再按结果排序
#nums.sort(key=DistanceFrom(5))
#[6, 4, 7, 3, 1]