adds to_dataframe() to QueryJob

Author: alixhami

bigquery/google/cloud/bigquery/job.py

@@ -1949,6 +1949,15 @@ def result(self, timeout=None, retry=DEFAULT_RETRY):
         return self._client.list_rows(dest_table, selected_fields=schema,
                                       retry=retry)
 
+    def to_dataframe(self):
+        import pandas as pd
+
+        iterator = self.result()
+        column_headers = [field.name for field in iterator.schema]
+        rows = [row.values() for row in iterator]
+
+        return pd.DataFrame(rows, columns=column_headers)
+
     def __iter__(self):
         return iter(self.result())
 

bigquery/tests/system.py

@@ -1242,6 +1242,23 @@ def test_query_iter(self):
         row_tuples = [r.values() for r in query_job]
         self.assertEqual(row_tuples, [(1,)])
 
+    def test_query_to_dataframe(self):
+        import pandas as pd
+
+        query = """
+            SELECT corpus AS title, COUNT(*) AS unique_words
+            FROM `bigquery-public-data.samples.shakespeare`
+            GROUP BY title
+            ORDER BY unique_words DESC
+            LIMIT 10"""
+
+        query_job = Config.CLIENT.query(query)
+        df = query_job.to_dataframe()
+
+        self.assertIsInstance(df, pd.DataFrame)
+        self.assertEqual(list(df), ['title', 'unique_words'])
+        self.assertEqual(len(df), 10)
+
     def test_query_table_def(self):
         gs_url = self._write_csv_to_storage(
             'bq_external_test' + unique_resource_id(), 'person_ages.csv',

bigquery/tests/unit/test_job.py

@@ -2720,6 +2720,70 @@ def test_reload_w_alternate_client(self):
         self.assertEqual(req['path'], PATH)
         self._verifyResourceProperties(job, RESOURCE)
 
+    def test_to_dataframe(self):
+        import pandas as pd
+
+        begun_resource = self._makeResource()
+        query_resource = {
+            'jobComplete': True,
+            'jobReference': {
+                'projectId': self.PROJECT,
+                'jobId': self.JOB_ID,
+            },
+            'schema': {
+                'fields': [
+                    {'name': 'name', 'type': 'STRING', 'mode': 'NULLABLE'},
+                    {'name': 'age', 'type': 'INTEGER', 'mode': 'NULLABLE'},
+                ],
+            },
+            'rows': [
+                {'f': [{'v': 'Phred Phlyntstone'}, {'v': '32'}]},
+                {'f': [{'v': 'Bharney Rhubble'}, {'v': '33'}]},
+                {'f': [{'v': 'Wylma Phlyntstone'}, {'v': '29'}]},
+                {'f': [{'v': 'Bhettye Rhubble'}, {'v': '27'}]},
+            ],
+        }
+        done_resource = copy.deepcopy(begun_resource)
+        done_resource['status'] = {'state': 'DONE'}
+        connection = _Connection(
+            begun_resource, query_resource, done_resource, query_resource)
+        client = _make_client(project=self.PROJECT, connection=connection)
+        job = self._make_one(self.JOB_ID, self.QUERY, client)
+        df = job.to_dataframe()
+
+        self.assertIsInstance(df, pd.DataFrame)
+        self.assertEqual(len(df), 4)
+        self.assertEqual(list(df), ['name', 'age'])
+
+    def test_to_dataframe_w_empty_results(self):
+        import pandas as pd
+
+        begun_resource = self._makeResource()
+        query_resource = {
+            'jobComplete': True,
+            'jobReference': {
+                'projectId': self.PROJECT,
+                'jobId': self.JOB_ID,
+            },
+            'schema': {
+                'fields': [
+                    {'name': 'name', 'type': 'STRING', 'mode': 'NULLABLE'},
+                    {'name': 'age', 'type': 'INTEGER', 'mode': 'NULLABLE'},
+                ],
+            },
+        }
+        done_resource = copy.deepcopy(begun_resource)
+        done_resource['status'] = {'state': 'DONE'}
+        connection = _Connection(
+            begun_resource, query_resource, done_resource, query_resource)
+        client = _make_client(project=self.PROJECT, connection=connection)
+        job = self._make_one(self.JOB_ID, self.QUERY, client)
+        df = job.to_dataframe()
+
+        self.assertIsInstance(df, pd.DataFrame)
+        self.assertEqual(len(df), 0)
+        self.assertEqual(list(df), ['name', 'age'])
+
     def test_iter(self):
         import types