提取从JSON特定值在Python

Question

我已经从呼叫的结果在Python JSON对象到一个API（使用的urllib2）生成如下：

results = urllib2.urlopen(req).read() 
json1 = json.loads(results) 

此生成包含类似的东西JSON对象以下（由于截断大小）：

"http://d.opencalais.com/dochash-1/895ba8ff-4c32-3ae1-9615-9a9a9a1bcb39/cat/1":{ 
    "_typeGroup":"topics", 
    "category":"http://d.opencalais.com/cat/Calais/Entertainment_Culture", 
    "classifierName":"Calais", 
    "categoryName":"Entertainment_Culture", 
    "score":1 
}, 
"http://d.opencalais.com/genericHasher-1/b6a2d07d-133b-35ad-85e2-54d524e750cf":{ 
    "_typeGroup":"entities", 
    "_type":"TVShow", 
    "name":"Hard Knocks", 
    "_typeReference":"http://s.opencalais.com/1/type/em/e/TVShow", 
    "instances":[ 
      { 
      "detection":"[ New York Jets during the summer of 2010 on HBO's ]Hard Knocks[.\n]", 
      "prefix":" New York Jets during the summer of 2010 on HBO's ", 
      "exact":"Hard Knocks", 
      "suffix":".\n", 
      "offset":135, 
      "length":11 
      } 
    ], 
    "relevance":0.5 
}, 

"http://d.opencalais.com/genericHasher-1/802a1ebb-7fac-354f-b02f-6ef8442950d3":{ 
    "_typeGroup":"entities", 
    "_type":"Organization", 
    "name":"New York Jets", 
    "organizationtype":"sports", 
    "nationality":"American", 
    "_typeReference":"http://s.opencalais.com/1/type/em/e/Organization", 
    "instances":[ 
      { 
      "detection":"[ Tebow caught a few training camp glimpses of the ]New York Jets[ during the summer of 2010 on HBO's Hard]", 
      "prefix":" Tebow caught a few training camp glimpses of the ", 
      "exact":"New York Jets", 
      "suffix":" during the summer of 2010 on HBO's Hard", 
      "offset":86, 
      "length":13 
      } 
    ], 
    "relevance":0.5 
} 

从这个JSON，我想提取“_type”和“名”仅在“typeGroup” ==“实体”。

例如，对于上面的JSON对象的输出应该是这样的：

TVShow: Hard Knocks 
Organization: New York Jets. 

可能有人请就如何做到这一点在Python帮助吗？

[UPDATE 1]

基于来自Jatin答案我尝试以下：

for key,value in json1.items(): 
    if value["_typeGroup"] == "entities": 
     print value['_type'], value['name'] 

然而，这导致错误KeyError异常： '_typeGroup'

我试图看如何按键和值打印如下：

for key,value in json1.items(): 
    print key,value 

这导致下面的输出（表示只是一个键，值对）：

http://d.opencalais.com/genericHasher-1/802a1ebb-7fac-354f-b02f-6ef8442950d3 {u'_typeReference': u'http://s.opencalais.com/1/type/em/e/Organization', u'_type': u'Organization', u'name': u'New York Jets', u'_typeGroup': u'entities', u'instances': [{u'suffix': u" during the summer of 2010 on HBO's Hard", u'prefix': u' Tebow caught a few training camp glimpses of the ', u'detection': u"[ Tebow caught a few training camp glimpses of the ]New York Jets[ during the summer of 2010 on HBO's Hard]", u'length': 13, u'offset': 86, u'exact': u'New York Jets'}], u'relevance': 0.5, u'nationality': u'American', u'organizationtype': u'sports'} 

这似乎是一个嵌套JSON。所以我尝试了以下按如下方式访问内部键值对：

for key,value in json1.items(): 
    val1 = value 
    for key,value in val1.items(): 
     if value["_typeGroup"] == "entities": 
      print value['_type'], value['name'] 

然而，它引发以下错误：

TypeError: string indices must be integers 

Answer 1

我想你会得到这个错误，因为你的JSON中的某些值没有_typeGroup。试试这个：

for key,value in x.items(): 
    if value.get("_typeGroup", "") == "entities": 
     print value['_type'], value['name'] 

Answer 2

for key,value in json1.items(): 
    if value.get('typeGroup') == "entities": 
     print value.get('_type'), value.get('name') 

试试这个，让我知道。 IT应该工作。