带有多个记录路径的json_normalize

Question

我正在使用此处json_normalize的pandas.json_normalize — pandas 1.0.3 documentation文档中提供的示例，很遗憾，我无法粘贴我的实际JSON，但此示例有效。从文档粘贴：

data = [{'state': 'Florida',
     'shortname': 'FL',
     'info': {'governor': 'Rick Scott'},
     'counties': [{'name': 'Dade', 'population': 12345},
                  {'name': 'Broward', 'population': 40000},
                  {'name': 'Palm Beach', 'population': 60000}]},
    {'state': 'Ohio',
     'shortname': 'OH',
     'info': {'governor': 'John Kasich'},
     'counties': [{'name': 'Summit', 'population': 1234},
                  {'name': 'Cuyahoga', 'population': 1337}]}]
result = json_normalize(data, 'counties', ['state', 'shortname',
                                           ['info', 'governor']])
result


         name  population    state shortname info.governor
0        Dade       12345   Florida    FL    Rick Scott
1     Broward       40000   Florida    FL    Rick Scott
2  Palm Beach       60000   Florida    FL    Rick Scott
3      Summit        1234   Ohio       OH    John Kasich
4    Cuyahoga        1337   Ohio       OH    John Kasich

如果JSON是下面的JSON而不是info是数组而不是dict的话：

data = [{'state': 'Florida',
     'shortname': 'FL',
     'info': [{'governor': 'Rick Scott'}, 
              {'governor': 'Rick Scott 2'}],
     'counties': [{'name': 'Dade', 'population': 12345},
                  {'name': 'Broward', 'population': 40000},
                  {'name': 'Palm Beach', 'population': 60000}]},
    {'state': 'Ohio',
     'shortname': 'OH',
     'info': [{'governor': 'John Kasich'}, 
              {'governor': 'John Kasich 2'}],
     'counties': [{'name': 'Summit', 'population': 1234},
                  {'name': 'Cuyahoga', 'population': 1337}]}]

如何使用json_normalize获得以下输出：

         name  population    state shortname info.governor
0        Dade       12345   Florida    FL    Rick Scott
1        Dade       12345   Florida    FL    Rick Scott 2
2     Broward       40000   Florida    FL    Rick Scott
3     Broward       40000   Florida    FL    Rick Scott 2
4  Palm Beach       60000   Florida    FL    Rick Scott
5  Palm Beach       60000   Florida    FL    Rick Scott 2
6      Summit        1234   Ohio       OH    John Kasich
7      Summit        1234   Ohio       OH    John Kasich 2    
8    Cuyahoga        1337   Ohio       OH    John Kasich
9    Cuyahoga        1337   Ohio       OH    John Kasich 2

Answer 1

json_normalize是为了方便而不是灵活性而设计的。它无法处理所有形式的JSON（JSON太灵活了，无法为其编写通用解析器）。

如何两次调用json_normalize，然后合并。假设每个状态仅在JSON中出现一次：

counties = json_normalize(data, 'counties', ['state', 'shortname'])
governors = json_normalize(data, 'info', ['state'])

result = counties.merge(governors, on='state')