我是python新手，正在尝试使用urllib从musicbrainz获取JSON数据，并且能够解析一些数据。但是，对于某些艺术家来说，JSON数据中的某些字段/键并不存在，因为它们可能不是必需的。我不确定如何根据进一步的筛选条件过滤获取的JSON数据。在

在下面的示例中，我只需要为release list&gt；>release&gt；>release group&gt；类型为“Single”的JSON数据过滤。获取的JSON每次可以有多达50次的迭代，但是我只提供feed以进一步过滤类别为“Single”的那些。请告诉我一个人该怎么做。谢谢！在

JSON示例：{

"created": "2012-12-27T13:22:55.834Z",

"recording-list": {

"count": 3,

"offset": 0,

"recording": [{

"score": "100",

"title": "Stronger",

"artist-credit": {

"name-credit": [{

"artist": {

"name": "Britney Spears",

"sort-name": "Spears, Britney"

}

}]

},

"release-list": {

"release": [{

"id": "13c5511f-1f99-4ffe-97d5-562c05e9d8d5",

"title": "Hit Hammer 2001 (disc 1)",

"status": "Official",

"artist-credit": {

"name-credit": [{

"artist": {

"id": "89ad4ac3-39f7-470e-963a-56509c546377",

"name": "Various Artists"

}

}]

},

"release-group": {

"id": "6c4c2cc3-3d8e-3a19-9d46-da076c34b6e9",

"type": "Compilation",

"primary-type": "Album",

"secondary-type-list": {

"secondary-type": ["Compilation"]

}

},

"medium-list": {

"track-count": 20,

"medium": [{

"position": 1,

"track-list": {

"count": 20,

"offset": 0,

"track": [{

"number": "1",

"title": "Stronger",

"length": 203266

}]

}

}]

}

}]

}

}, {

"id": "feb9acbf-1d3d-4395-9512-bfbdcfa72eb9",

"score": "100",

"title": "Stronger",

"artist-credit": {

"name-credit": [{

"joinphrase": "",

"artist": {

"name": "Britney Spears",

"sort-name": "Spears, Britney"

}

}]

},

"release-list": {

"release": [{

"id": "45e2a271-2f6b-4029-b11e-b6d94d169f9a",

"title": "Stronger: The Remixes",

"status": "Official",

"release-group": {

"id": "4d018ba8-f05e-4817-8c70-34307161a0fc",

"type": "Single",

"primary-type": "Single"

},

"date": "2000-12-12",

"country": "US",

"medium-list": {

"track-count": 6,

"medium": [{

"position": 1,

"format": "CD",

"track-list": {

"count": 6,

"offset": 0,

"track": [{

"number": "1",

"title": "Stronger",

"length": 203000

}]

}

}]

}

}]

},

"puid-list": {

"puid": [{

"id": "28550845-c68a-314d-90c1-010dff730f4a"

}]

}

}]

}

}

Python代码：

^{pr2}$