问题描述
我正在尝试将嵌套的JSON转换为Pandas数据框.我一直成功地使用json_normalize，直到遇到某个JSON.我制作了一个较小的版本来重新创建问题.
I'm trying to convert a nested JSON to a Pandas dataframe. I've been using json_normalize with success until I came across a certain JSON. I've made a smaller version of it to recreate the problem.
from pandas.io.json import json_normalize
json=[{"events": [{"schedule": {"date": "2015-08-27",
"location": {"building": "BDC", "floor": 5},
"ID": 815},
"group": "A"},
{"schedule": {"date": "2015-08-27",
"location": {"building": "BDC", "floor": 5},
"ID": 816},
"group": "A"}]}]
然后我运行:
json_normalize(json[0],'events',[['schedule','date'],['schedule','location','building'],['schedule','location','floor']])
期望看到这样的东西:
ID group schedule.date schedule.location.building schedule.location.floor
'815' 'A' '2015-08-27' 'BDC' 5
'816' 'A' '2015-08-27' 'BDC' 5
但是相反，我得到了这个错误:
But instead I get this error:
In [2]: json_normalize(json[0],'events',[['schedule','date'],['schedule','location','building'],['schedule','location','floor']])
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-2-b588a9e3ef1d> in <module>()
----> 1 json_normalize(json[0],'events',[['schedule','date'],['schedule','location','building'],['schedule','location','floor']])
/Users/logan/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/pandas/io/json.pyc in json_normalize(data, record_path, meta, meta_prefix, record_prefix)
739 records.extend(recs)
740
--> 741 _recursive_extract(data, record_path, {}, level=0)
742
743 result = DataFrame(records)
/Users/logan/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/pandas/io/json.pyc in _recursive_extract(data, path, seen_meta, level)
734 meta_val = seen_meta[key]
735 else:
--> 736 meta_val = _pull_field(obj, val[level:])
737 meta_vals[key].append(meta_val)
738
/Users/logan/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/pandas/io/json.pyc in _pull_field(js, spec)
674 if isinstance(spec, list):
675 for field in spec:
--> 676 result = result[field]
677 else:
678 result = result[spec]
KeyError: 'schedule'
推荐答案
在这种情况下，我认为您将使用此方法:
In this case, I think you'd just use this:
In [57]: json_normalize(data[0]['events'])
Out[57]:
group schedule.ID schedule.date schedule.location.building \
0 A 815 2015-08-27 BDC
1 A 816 2015-08-27 BDC
schedule.location.floor
0 5
1 5
meta路径([['schedule','date']...])用于以与记录相同的嵌套级别(即与事件"相同的级别)指定数据.看起来json_normalize不能很好地处理带有嵌套列表的字典，因此，如果实际数据要复杂得多，则可能需要进行一些手动重塑.
The meta paths ([['schedule','date']...]) are for specifying data at the same level of nesting as your records, i.e. at the same level as 'events'. It doesn't look like json_normalize handles dicts with nested lists particularly well, so you may need to do some manual reshaping if your actual data is much more complicated.
这篇关于大 pandas json_normalize产生令人困惑的`KeyError`消息?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！