DOC: add example on json_normalize (#16438)

Author: zzgao

doc/source/io.rst

@@ -2020,6 +2020,13 @@ into a flat table.
 .. ipython:: python
 
    from pandas.io.json import json_normalize
+   data = [{'id': 1, 'name': {'first': 'Coleen', 'last': 'Volk'}},
+           {'name': {'given': 'Mose', 'family': 'Regner'}},
+           {'id': 2, 'name': 'Faye Raker'}]
+   json_normalize(data)
+
+.. ipython:: python
+
    data = [{'state': 'Florida',
              'shortname': 'FL',
              'info': {

pandas/io/json/normalize.py

@@ -135,6 +135,16 @@ def json_normalize(data, record_path=None, meta=None,
     Examples
     --------
 
+    >>> from pandas.io.json import json_normalize
+    >>> data = [{'id': 1, 'name': {'first': 'Coleen', 'last': 'Volk'}},
+    ...         {'name': {'given': 'Mose', 'family': 'Regner'}},
+    ...         {'id': 2, 'name': 'Faye Raker'}]
+    >>> json_normalize(data)
+        id        name name.family name.first name.given name.last
+    0  1.0         NaN         NaN     Coleen        NaN      Volk
+    1  NaN         NaN      Regner        NaN       Mose       NaN
+    2  2.0  Faye Raker         NaN        NaN        NaN       NaN
+
     >>> data = [{'state': 'Florida',
     ...          'shortname': 'FL',
     ...          'info': {
@@ -150,7 +160,6 @@ def json_normalize(data, record_path=None, meta=None,
     ...          },
     ...          'counties': [{'name': 'Summit', 'population': 1234},
     ...                       {'name': 'Cuyahoga', 'population': 1337}]}]
-    >>> from pandas.io.json import json_normalize
     >>> result = json_normalize(data, 'counties', ['state', 'shortname',
     ...                                           ['info', 'governor']])
     >>> result