# _*_ coding: utf-8 _*_ """ python_magic_methods.py by xianhu """ # 定义一个能够自动比较大小的People类 class People(object): def __init__(self, name, age): self.name = name self.age = age return def __str__(self): return self.name + ":" + str(self.age) def __lt__(self, other): return self.name < other.name if self.name != other.name else self.age < other.age print("\t".join([str(item) for item in sorted([People("abc", 18), People("abe", 19), People("abe", 12), People("abc", 17)])])) # Python实现任意深度的赋值 例如a[0] = 'value1'; a[1][2] = 'value2'; a[3][4][5] = 'value3' class MyDict(dict): def __setitem__(self, key, value): # 该函数不做任何改动 这里只是为了输出 print("setitem:", key, value, self) super().__setitem__(key, value) return def __getitem__(self, item): # 主要技巧在该函数 print("getitem:", item, self) # 基本思路: a[1][2]赋值时 需要先取出a[1] 然后给a[1]的[2]赋值 if item not in self: # 如果a[1]不存在 temp = MyDict() # 则需要新建一个dict super().__setitem__(item, temp) # 并使得a[1] = dict return temp # 返回a[1] 使得a[1][2] = value有效 return super().__getitem__(item) # 如果a[1]存在 则直接返回a[1] # 使用例子: test = MyDict() test[0] = 'test' test[1][2] = 'test1' test[3][4][5] = 'test2' print("==========================")