如何在python中创建一个不可变的字典？ [英] How to create an immutable dictionary in python?

问题描述

我想在python中子类 dict ，这样子类的所有字典都是不可变的。 / p>

我不明白 __ hash __ 如何影响不可变性，因为在我的理解中，它只是表示平等或不相等的对象！

因此，可以 __ hash __ 用于实现不变性？如何？

更新：

目标是，可用作dict，必须作为全局变量共享。

解决方案

找到官方参考资料：

  class imdict（dict）：
 def __hash __（self）：
 return id（self）
 
 def _immutable （self，* args，** kws）：
 raise TypeError（'object is immutable'）
 
 __setitem__ = _immutable 
 __delitem__ = _immutable 
 clear = _immutable 
 update = _immutable 
 setdefault = _immutable 
 pop = _immutable 
 popitem = _immutable 
  

b $ b

归属： http://www.python.org/dev/ peps / pep-0351 /

I want to subclass dict in python such that all the dictionaries of the sub-class are immutable.

I don't understand how does __hash__ affects the immutability, since in my understanding it just signifies the equality or non-equality of objects !

So, can __hash__ be used to implement immutability ? How ?

Update:

Objective is that common response from an API is available as a dict, which has to be shared as a global variable. So, that needs to be intact no matter what ?

解决方案

Found an Official reference :

class imdict(dict):
def __hash__(self):
    return id(self)

def _immutable(self, *args, **kws):
    raise TypeError('object is immutable')

__setitem__ = _immutable
__delitem__ = _immutable
clear       = _immutable
update      = _immutable
setdefault  = _immutable
pop         = _immutable
popitem     = _immutable

Attribution : http://www.python.org/dev/peps/pep-0351/

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