字典键unpythonic的Javascript风格点符号？ [英] Javascript style dot notation for dictionary keys unpythonic?

问题描述

我已经开始使用这样的结构：

I've started to use constructs like these:

class DictObj(object):
    def __init__(self):
        self.d = {}
    def __getattr__(self, m):
        return self.d.get(m, None)
    def __setattr__(self, m, v):
        super.__setattr__(self, m, v)

在这个线程，我修改了DictObj实现为：

Update: based on this thread, I've revised the DictObj implementation to:

class dotdict(dict):
    def __getattr__(self, attr):
        return self.get(attr, None)
    __setattr__= dict.__setitem__
    __delattr__= dict.__delitem__

class AutoEnum(object):
    def __init__(self):
        self.counter = 0
        self.d = {}
    def __getattr__(self, c):
        if c not in self.d:
            self.d[c] = self.counter
            self.counter += 1        
        return self.d[c]

其中DictObj是可以通过点符号访问的字典：

where DictObj is a dictionary that can be accessed via dot notation:

d = DictObj()
d.something = 'one'

发现它比美观更美观 d ['something'] 。请注意，访问未定义的键将返回None而不是引发异常，这也很好。

I find it more aesthetically pleasing than d['something']. Note that accessing an undefined key returns None instead of raising an exception, which is also nice.

更新：Smashery是一个好点，mhawke扩展了一个更容易的解决方案。我想知道是否有任何不良的副作用使用 dict 而不是定义一个新的字典;

Update: Smashery makes a good point, which mhawke expands on for an easier solution. I'm wondering if there are any undesirable side effects of using dict instead of defining a new dictionary; if not, I like mhawke's solution a lot.

AutoEnum是一个自动递增的Enum，使用像这样：

AutoEnum is an auto-incrementing Enum, used like this:

CMD = AutoEnum()

cmds = {
    "peek":  CMD.PEEK,
    "look":  CMD.PEEK,
    "help":  CMD.HELP,
    "poke":  CMD.POKE,
    "modify": CMD.POKE,
}

两个都对我很好，但我对他们感到不爽。

Both are working well for me, but I'm feeling unpythonic about them.

这些实际上是不好的结构吗？

Are these in fact bad constructs?

推荐答案

DictObj类的简单版本：

This is a simpler version of your DictObj class:

class DictObj(object):
    def __getattr__(self, attr):
        return self.__dict__.get(attr)

>>> d = DictObj()
>>> d.something = 'one'
>>> print d.something
one
>>> print d.somethingelse
None
>>> 

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