BUG: fix nested meta path bug in json_normalize (GH 27220)

Author: another-green

pandas/io/json/_normalize.py

@@ -310,18 +310,16 @@ def _recursive_extract(data, path, seen_meta, level=0):
                     # is at the meta path end
                     if level + 1 > len(val):
                         meta_val = seen_meta[key]
-                        meta_vals[key].append(meta_val)
                     # Extract the value of the key from seen_meta when
                     # meta path and record path are on two branches
                     elif seen_meta:
-                        meta_val = seen_meta[key]
-                        meta_vals[key] += [
-                            # The list case
-                            meta_val[ind][val[level]]
-                            if isinstance(meta_val, list)
-                            # The dict case
-                            else meta_val[val[level]]
-                        ]
+                        meta_val_obj = seen_meta[key]
+                        # Both the list case and the dict case are covered
+                        meta_val = (
+                            meta_val_obj[ind][val[level]]
+                            if isinstance(meta_val_obj, list)
+                            else meta_val_obj[val[level]]
+                        )
                     # At top level, seen_meta is empty, pull from data
                     # directly and raise KeyError if not found
                     else:
@@ -336,7 +334,7 @@ def _recursive_extract(data, path, seen_meta, level=0):
                                     "errors='ignore' as key "
                                     "{err} is not always present".format(err=e)
                                 )
-                        meta_vals[key].append(meta_val)
+                    meta_vals[key].append(meta_val)
 
                 records.extend(recs)
 

pandas/tests/io/json/test_normalize.py

@@ -1,5 +1,4 @@
 import json
-import sys
 
 import numpy as np
 import pytest
@@ -288,13 +287,13 @@ def test_shallow_nested(self):
         expected = DataFrame(ex_data, columns=result.columns)
         tm.assert_frame_equal(result, expected)
 
-    @pytest.mark.skipif(sys.version_info < (3, 6), reason="drop support for 3.5 soon")
+    @pytest.mark.skipif(not PY36, reason="drop support for 3.5 soon")
     def test_nested_meta_path_with_nested_record_path(self, state_data):
         # GH 27220
         result = json_normalize(
-            state_data,
-            ["counties", "name"],
-            ["state", "shortname", ["info", "governor"]],
+            data=state_data,
+            record_path=["counties", "name"],
+            meta=["state", "shortname", ["info", "governor"]],
             errors="ignore",
         )
         ex_data = {