Fixed as instructed in pull request page

Author: dickreuter

doc/source/whatsnew/v0.20.0.txt

@@ -61,6 +61,8 @@ Other enhancements
 - The ``usecols`` argument in ``pd.read_csv`` now accepts a callable function as a value  (:issue:`14154`)
 - ``pd.DataFrame.plot`` now prints a title above each subplot if ``suplots=True`` and ``title`` is a list of strings (:issue:`14753`)
 - ``pd.Series.interpolate`` now supports timedelta as an index type with ``method='time'`` (:issue:`6424`)
+- ``pandas.io.json.json_normalize`` If meta keys are not always present a new option to set errors="ignore" (:issue:`14583`)
+
 
 .. _whatsnew_0200.api_breaking:
 

pandas/io/json.py

@@ -849,8 +849,9 @@ def _recursive_extract(data, path, seen_meta, level=0):
                             if errors == 'ignore':
                                 meta_val = np.nan
                             else:
-                                raise KeyError(
-                                    "Try running with errors='ignore' as the following key may not always be present: " + str(e))
+                                raise \
+                                    KeyError(
+                                    "Try running with errors='ignore' as key may not always be present: %s", e)
                     meta_vals[key].append(meta_val)
 
                 records.extend(recs)

pandas/io/tests/json/test_json_norm.py

@@ -226,9 +226,9 @@ def test_nested_flattens(self):
         self.assertEqual(result, expected)
 
 
-    def test_json_normalise_fix(self):
-        # issue 14505
-        j = {
+    def test_json_normalize_errors(self):
+        # If meta keys are not always present a new option to set errors='ignore' has been implemented (:issue:`14583`)
+        i = {
             "Trades": [{
                 "general": {
                     "tradeid": 100,
@@ -268,7 +268,7 @@ def test_json_normalise_fix(self):
             }
             ]
         }
-        j = json_normalize(data=j['Trades'], record_path=[['general', 'stocks']],
+        j = json_normalize(data=i['Trades'], record_path=[['general', 'stocks']],
                            meta=[['general', 'tradeid'], ['general', 'trade_version']], errors='ignore')
         expected={'general.trade_version': {0: 1.0, 1: 1.0, 2: '', 3: ''},
          'general.tradeid': {0: 100, 1: 100, 2: 100, 3: 100},
@@ -278,6 +278,12 @@ def test_json_normalise_fix(self):
 
         self.assertEqual(j.fillna('').to_dict(), expected)
 
+        self.assertRaises(KeyError,
+                json_normalize, data=i['Trades'], record_path=[['general', 'stocks']],
+                           meta=[['general', 'tradeid'], ['general', 'trade_version']], errors='raise'
+                          )
+
+
 if __name__ == '__main__':
     nose.runmodule(argv=[__file__, '-vvs', '-x', '--pdb',
                          '--pdb-failure', '-s'], exit=False)