L2SS-845: Return arrays as [y][x] just like Tango uses

Closes L2SS-845

lofar_station_client/requests/prometheus.py

@@ -211,9 +211,9 @@ class PrometheusRequests:
                              pass as `json["data"]["result"]` from raw json.
         """
 
-        def ord_index(metric: dict) -> str:
+        def ord_index(metric: dict) -> Tuple[str]:
             """Generate the ordered dict index from json metric"""
-            return f"{metric['x']}.{metric['y']}"
+            return (metric["x"], metric["y"])
 
         result_dict = OrderedDict()
         for json_result in json_results:
@@ -233,15 +233,14 @@ class PrometheusRequests:
     def _expand_convert_results_3d(
         merged_results: OrderedDict,
     ) -> List[List[List[Tuple[datetime, any]]]]:
-        """Expand the results into [x][y][tuple[datetime, value]] and convert values
+        """Expand the results into [y][x][tuple[datetime, value]] and convert values
 
         :param merged_results: Result from _merge_result_data
         """
 
-        def str_to_coords(coordinate: str) -> (int, int):
+        def str_to_coords(coordinate: Tuple[str]) -> (int, int):
             """Convert the string coordinate"""
-            split = coordinate.split(".", 1)
-            return int(split[0]), int(split[1])
+            return int(coordinate[0]), int(coordinate[1])
 
         def convert_row(row: List[any], converter: Callable):
             return datetime.fromtimestamp(row[0]), converter(row[1])
@@ -250,13 +249,15 @@ class PrometheusRequests:
         for key, values in merged_results.items():
             x_index, y_index = str_to_coords(key)
 
+            # Store as [y][x], just like Tango
+
             # Ensure outermost array sufficiently sized
-            while len(results) <= x_index:
+            while len(results) <= y_index:
                 results.append([[]])
 
             # Ensure internal array sufficiently sized
-            while len(results[x_index]) <= y_index:
-                results[x_index].append([])
+            while len(results[y_index]) <= x_index:
+                results[y_index].append([])
 
             # Per result determine the callable type converter
             type_converter = PrometheusRequests._get_type_converter(
@@ -264,6 +265,6 @@ class PrometheusRequests:
             )
 
             result = [convert_row(row, type_converter) for row in values["values"]]
-            results[x_index][y_index].extend(result)
+            results[y_index][x_index].extend(result)
 
         return results