带有非常嵌套的json的pandas.io.json.json_normalize

Question

我一直在尝试normalize一个非常嵌套的json文件,我稍后会分析.我正在努力的是如何超过一个级别来规范化.

我浏览了pandas.io.json.json_normalize文档,因为它完全符合我的要求.

我能够将其中的一部分标准化,现在了解字典是如何工作的,但我仍然不在那里.

使用以下代码,我只能获得第一级.

import json
import pandas as pd
from pandas.io.json import json_normalize

with open('authors_sample.json') as f:
    d = json.load(f)

raw = json_normalize(d['hits']['hits'])

authors = json_normalize(data = d['hits']['hits'], 
                         record_path = '_source', 
                         meta = ['_id', ['_source', 'journal'], ['_source', 'title'], 
                                 ['_source', 'normalized_venue_name']
                                 ])

我试图用下面的代码'挖掘''作者'字典,但是record_path = ['_source', 'authors']抛出了我TypeError: string indices must be integers.据我所知json_normalize,逻辑应该是好的,但我仍然不太明白如何与dictvs 潜入json list.

我甚至经历了这个简单的例子.

authors = json_normalize(data = d['hits']['hits'], 
                         record_path = ['_source', 'authors'], 
                         meta = ['_id', ['_source', 'journal'], ['_source', 'title'], 
                                 ['_source', 'normalized_venue_name']
                                 ])

下面是json文件的一大块(5条记录).

{u'_shards': {u'failed': 0, u'successful': 5, u'total': 5},
 u'hits': {u'hits': [{u'_id': u'7CB3F2AD',
    u'_index': u'scibase_listings',
    u'_score': 1.0,
    u'_source': {u'authors': None,
     u'deleted': 0,
     u'description': None,
     u'doi': u'',
     u'is_valid': 1,
     u'issue': None,
     u'journal': u'Physical Review Letters',
     u'link': None,
     u'meta_description': None,
     u'meta_keywords': None,
     u'normalized_venue_name': u'phys rev lett',
     u'pages': None,
     u'parent_keywords': [u'Chromatography',
      u'Quantum mechanics',
      u'Particle physics',
      u'Quantum field theory',
      u'Analytical chemistry',
      u'Quantum chromodynamics',
      u'Physics',
      u'Mass spectrometry',
      u'Chemistry'],
     u'pub_date': u'1987-03-02 00:00:00',
     u'pubtype': None,
     u'rating_avg_weighted': 0,
     u'rating_clarity': 0.0,
     u'rating_clarity_weighted': 0.0,
     u'rating_innovation': 0.0,
     u'rating_innovation_weighted': 0.0,
     u'rating_num_weighted': 0,
     u'rating_reproducability': 0,
     u'rating_reproducibility_weighted': 0.0,
     u'rating_versatility': 0.0,
     u'rating_versatility_weighted': 0.0,
     u'review_count': 0,
     u'tag': [u'mass spectra', u'elementary particles', u'bound states'],
     u'title': u'Evidence for a new meson: A quasinuclear NN-bar bound state',
     u'userAvg': 0.0,
     u'user_id': None,
     u'venue_name': u'Physical Review Letters',
     u'views_count': 0,
     u'volume': None},
    u'_type': u'listing'},
   {u'_id': u'7AF8EBC3',
    u'_index': u'scibase_listings',
    u'_score': 1.0,
    u'_source': {u'authors': [{u'affiliations': [u'Punjabi University'],
       u'author_id': u'780E3459',
       u'author_name': u'munish puri'},
      {u'affiliations': [u'Punjabi University'],
       u'author_id': u'48D92C79',
       u'author_name': u'rajesh dhaliwal'},
      {u'affiliations': [u'Punjabi University'],
       u'author_id': u'7D9BD37C',
       u'author_name': u'r s singh'}],
     u'deleted': 0,
     u'description': None,
     u'doi': u'',
     u'is_valid': 1,
     u'issue': None,
     u'journal': u'Journal of Industrial Microbiology & Biotechnology',
     u'link': None,
     u'meta_description': None,
     u'meta_keywords': None,
     u'normalized_venue_name': u'j ind microbiol biotechnol',
     u'pages': None,
     u'parent_keywords': [u'Nuclear medicine',
      u'Psychology',
      u'Hydrology',
      u'Chromatography',
      u'X-ray crystallography',
      u'Nuclear fusion',
      u'Medicine',
      u'Fluid dynamics',
      u'Thermodynamics',
      u'Physics',
      u'Gas chromatography',
      u'Radiobiology',
      u'Engineering',
      u'Organic chemistry',
      u'High-performance liquid chromatography',
      u'Chemistry',
      u'Organic synthesis',
      u'Psychotherapist'],
     u'pub_date': u'2008-04-04 00:00:00',
     u'pubtype': None,
     u'rating_avg_weighted': 0,
     u'rating_clarity': 0.0,
     u'rating_clarity_weighted': 0.0,
     u'rating_innovation': 0.0,
     u'rating_innovation_weighted': 0.0,
     u'rating_num_weighted': 0,
     u'rating_reproducability': 0,
     u'rating_reproducibility_weighted': 0.0,
     u'rating_versatility': 0.0,
     u'rating_versatility_weighted': 0.0,
     u'review_count': 0,
     u'tag': [u'flow rate',
      u'operant conditioning',
      u'packed bed reactor',
      u'immobilized enzyme',
      u'specific activity'],
     u'title': u'Development of a stable continuous flow immobilized enzyme reactor for the hydrolysis of inulin',
     u'userAvg': 0.0,
     u'user_id': None,
     u'venue_name': u'Journal of Industrial Microbiology & Biotechnology',
     u'views_count': 0,
     u'volume': None},
    u'_type': u'listing'},
   {u'_id': u'7521A721',
    u'_index': u'scibase_listings',
    u'_score': 1.0,
    u'_source': {u'authors': [{u'author_id': u'7FF872BC',
       u'author_name': u'barbara eileen ryan'}],
     u'deleted': 0,
     u'description': None,
     u'doi': u'',
     u'is_valid': 1,
     u'issue': None,
     u'journal': u'The American Historical Review',
     u'link': None,
     u'meta_description': None,
     u'meta_keywords': None,
     u'normalized_venue_name': u'american historical review',
     u'pages': None,
     u'parent_keywords': [u'Social science',
      u'Politics',
      u'Sociology',
      u'Law'],
     u'pub_date': u'1992-01-01 00:00:00',
     u'pubtype': None,
     u'rating_avg_weighted': 0,
     u'rating_clarity': 0.0,
     u'rating_clarity_weighted': 0.0,
     u'rating_innovation': 0.0,
     u'rating_innovation_weighted': 0.0,
     u'rating_num_weighted': 0,
     u'rating_reproducability': 0,
     u'rating_reproducibility_weighted': 0.0,
     u'rating_versatility': 0.0,
     u'rating_versatility_weighted': 0.0,
     u'review_count': 0,
     u'tag': [u'social movements'],
     u'title': u"Feminism and the women's movement : dynamics of change in social movement ideology, and activism",
     u'userAvg': 0.0,
     u'user_id': None,
     u'venue_name': u'The American Historical Review',
     u'views_count': 0,
     u'volume': None},
    u'_type': u'listing'},
   {u'_id': u'7DAEB9A4',
    u'_index': u'scibase_listings',
    u'_score': 1.0,
    u'_source': {u'authors': [{u'author_id': u'0299B8E9',
       u'author_name': u'fraser j harbutt'}],
     u'deleted': 0,
     u'description': None,
     u'doi': u'',
     u'is_valid': 1,
     u'issue': None,
     u'journal': u'The American Historical Review',
     u'link': None,
     u'meta_description': None,
     u'meta_keywords': None,
     u'normalized_venue_name': u'american historical review',
     u'pages': None,
     u'parent_keywords': [u'Superconductivity',
      u'Nuclear fusion',
      u'Geology',
      u'Chemistry',
      u'Metallurgy'],
     u'pub_date': u'1988-01-01 00:00:00',
     u'pubtype': None,
     u'rating_avg_weighted': 0,
     u'rating_clarity': 0.0,
     u'rating_clarity_weighted': 0.0,
     u'rating_innovation': 0.0,
     u'rating_innovation_weighted': 0.0,
     u'rating_num_weighted': 0,
     u'rating_reproducability': 0,
     u'rating_reproducibility_weighted': 0.0,
     u'rating_versatility': 0.0,
     u'rating_versatility_weighted': 0.0,
     u'review_count': 0,
     u'tag': [u'iron'],
     u'title': u'The iron curtain : Churchill, America, and the origins of the Cold War',
     u'userAvg': 0.0,
     u'user_id': None,
     u'venue_name': u'The American Historical Review',
     u'views_count': 0,
     u'volume': None},
    u'_type': u'listing'},
   {u'_id': u'7B3236C5',
    u'_index': u'scibase_listings',
    u'_score': 1.0,
    u'_source': {u'authors': [{u'author_id': u'7DAB7B72',
       u'author_name': u'richard m freeland'}],
     u'deleted': 0,
     u'description': None,
     u'doi': u'',
     u'is_valid': 1,
     u'issue': None,
     u'journal': u'The American Historical Review',
     u'link': None,
     u'meta_description': None,
     u'meta_keywords': None,
     u'normalized_venue_name': u'american historical review',
     u'pages': None,
     u'parent_keywords': [u'Political Science', u'Economics'],
     u'pub_date': u'1985-01-01 00:00:00',
     u'pubtype': None,
     u'rating_avg_weighted': 0,
     u'rating_clarity': 0.0,
     u'rating_clarity_weighted': 0.0,
     u'rating_innovation': 0.0,
     u'rating_innovation_weighted': 0.0,
     u'rating_num_weighted': 0,
     u'rating_reproducability': 0,
     u'rating_reproducibility_weighted': 0.0,
     u'rating_versatility': 0.0,
     u'rating_versatility_weighted': 0.0,
     u'review_count': 0,
     u'tag': [u'foreign policy'],
     u'title': u'The Truman Doctrine and the origins of McCarthyism : foreign policy, domestic politics, and internal security, 1946-1948',
     u'userAvg': 0.0,
     u'user_id': None,
     u'venue_name': u'The American Historical Review',
     u'views_count': 0,
     u'volume': None},
    u'_type': u'listing'}],
  u'max_score': 1.0,
  u'total': 36429433},
 u'timed_out': False,
 u'took': 170}

Answer 1

在大熊猫的例子中(下面)括号是什么意思？是否有一个逻辑可以跟随[]更深入.

除了选定的行之外,其中的每个元素['state', 'shortname', ['info', 'governor']]都是要包含的元素的路径.该参数设置应该生产什么行,而第二个参数补充说,将包含这些行的元数据.'counties'

每个都是路径,列表是嵌套结构.在这个例子中输出,您看到的相应值state,shortname和info.governor列.

在您的示例JSON中,有几个嵌套列表可以使用第一个参数进行提升,就像'counties'示例中所做的那样.该数据结构中唯一的例子是嵌套'authors'密钥; 您必须提取每个['_source', 'authors']路径,之后您可以从父对象添加其他键以扩充这些行:

>>> json_normalize(raw, [['_source', 'authors']], ['_id', ['_source', 'journal'], ['_source', 'title']])
                      affiliations author_id          author_name       _id  \
0                              NaN  166468F4  a bowdoin van riper  7FDFEB02
1                              NaN  81070854   jeffrey h schwartz  7FDFEB02
2  [Pennsylvania State University]  7E15BDFA       roger l geiger  7538108B

                  _source.journal  \
0  The American Historical Review
1  The American Historical Review
2  The American Historical Review

                                       _source.title
0  Men Among the Mammoths: Victorian Science and ...
1  Men Among the Mammoths: Victorian Science and ...
2  Elizabeth Popp Berman. Creating the Market Uni...

因此,这是作者的数据框,为每个作者添加了元数据(_id值,期刊名称和文章标题).

注意第一个参数的路径; 如果要列出嵌套路径,则需要提供路径列表(即使它只是一条路径); 只需['_source', 'authors']查找两个行源,每个源都是一个简单的顶级名称.

然后第二个参数_id从最外面的对象中提取键,但标题和日志名称是list路径,因为它们也是嵌套的.

Answer 2

您还可以查看库flatten_json，它不需要像json_normalize中那样编写列层次结构：

from flatten_json import flatten

data = d['hits']['hits']
dict_flattened = (flatten(record, '.') for record in data)
df = pd.DataFrame(dict_flattened)
print(df)

参见https://github.com/amirziai/flatten。