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