python - 在 python 中从 JSON 解码对象

Question

我有一个如下所示的类:

class Car:
def __init__(self, name, colour, wheels):
    self.name = name
    self.colour = colour
    self.wheels = wheels

我想从 JSON 文件创建上述类的对象，它看起来像这样，但有很多条目:

  "Cars":[
  {
  "name": "Golf",
  "colour": "red",
  "wheels": 4,
  },
  {
  "name": "Up",
  "colour": "green",
  "wheels": 3,
  }
  ]

然后将它们添加到布局为 {"name":object} 的字典中。我已经查看了可用的不同教程和示例，但大多数似乎都是关于转储对象，而不是将它们拉出并从中重新创建对象。

Answer 1

如果您的文件确保始终具有相同的顺序(名称、颜色、轮子)和相同的尺寸(3 个项目)，则可以使用如下内容:

JSON 文件 (foo.jsonp>

{"Cars":{
"Golf":{
  "name": "Golf",
  "colour": "red",
  "wheels": 4
  },  
"Robin": {
  "name": "Up",
  "colour": "green",
  "wheels": 3
  }
  } 
}


>>> import json
>>> import collections
>>> data = ''.join(i.replace('\n','') for i in open('foo.json').readlines())
>>> decoder = json.JSONDecoder(object_pairs_hook=collections.OrderedDict)
>>>
>>> class Car(object):
...  def __init__(self, name, colour, wheels):
...     self.name = name
...     self.colour = colour
...     self.wheels = wheels
... 
>>> j = decoder.decode(data)
>>> 
>>> out_dict = {car:Car(*j['Cars'][car].values()) for car in j['Cars']}
>>>
>>> golf = out_dict['Golf']
>>> golf.name
u'Golf'
>>> golf.colour
u'red'
>>> golf.wheels
4