通过属性和索引访问递归访问字典? [英] Recursively access dict via attributes as well as index access?

问题描述

我希望能够做这样的事情:

I'd like to be able to do something like this:

from dotDict import dotdictify

life = {'bigBang':
           {'stars':
               {'planets': []}
           }
       }

dotdictify(life)

# This would be the regular way:
life['bigBang']['stars']['planets'] = {'earth': {'singleCellLife': {}}}
# But how can we make this work?
life.bigBang.stars.planets.earth = {'singleCellLife': {}}

#Also creating new child objects if none exist, using the following syntax:
life.bigBang.stars.planets.earth.multiCellLife = {'reptiles':{},'mammals':{}}

我的动机是提高代码的简洁性，并在可能的情况下使用与 Javascript 类似的语法来访问 JSON 对象，以实现高效的跨平台开发.(我也使用 Py2JS 和类似的.)

My motivations are to improve the succinctness of the code, and if possible use similar syntax to Javascript for accessing JSON objects for efficient cross platform development. (I also use Py2JS and similar.)

推荐答案

这是创造这种体验的一种方法:

Here's one way to create that kind of experience:

class DotDictify(dict):
    MARKER = object()

    def __init__(self, value=None):
        if value is None:
            pass
        elif isinstance(value, dict):
            for key in value:
                self.__setitem__(key, value[key])
        else:
            raise TypeError('expected dict')

    def __setitem__(self, key, value):
        if isinstance(value, dict) and not isinstance(value, DotDictify):
            value = DotDictify(value)
        super(DotDictify, self).__setitem__(key, value)

    def __getitem__(self, key):
        found = self.get(key, DotDictify.MARKER)
        if found is DotDictify.MARKER:
            found = DotDictify()
            super(DotDictify, self).__setitem__(key, found)
        return found

    __setattr__, __getattr__ = __setitem__, __getitem__


if __name__ == '__main__':

    life = {'bigBang':
               {'stars':
                   {'planets': {}  # Value changed from []
                   }
               }
           }

    life = DotDictify(life)
    print(life.bigBang.stars.planets)  # -> []
    life.bigBang.stars.planets.earth = {'singleCellLife' : {}}
    print(life.bigBang.stars.planets)  # -> {'earth': {'singleCellLife': {}}}

这篇关于通过属性和索引访问递归访问字典?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！