Fix Monitors.AsMatrix, add utils.monitor_to_dataframe and related test.

Closes #12

Author: PMeira

opendssdirect/Monitors.py

@@ -2,6 +2,7 @@
 from __future__ import absolute_import
 import numpy as np
 from ._utils import (
+    api_util,
     lib,
     codec,
     CheckForError,
@@ -201,7 +202,7 @@ def AsMatrix():
     Matrix of the active monitor, containing the hour vector, seconds vector, and all channels (index 2 = channel 1).
     If you need multiple channels, prefer using this function as it processes the monitor byte-stream once.
     """
-    buffer = get_int8_array(lib.Monitors_Get_ByteStream)
+    buffer = api_util.get_int8_array(lib.Monitors_Get_ByteStream)
     CheckForError()
     if len(buffer) <= 1:
         return None

opendssdirect/utils.py

@@ -3,7 +3,7 @@
 import inspect
 import warnings
 
-from ._utils import get_string
+from ._utils import get_string, dss_py
 
 is_pandas_installed = True
 
@@ -235,6 +235,32 @@ def meters_to_dataframe(dss=None):
     return to_dataframe(dss.Meters)
 
 
+def monitor_to_dataframe(dss=None):
+    """
+    Return the data from current active monitor as a Pandas DataFrame
+    """
+    if dss is None:
+        import opendssdirect as dss
+
+    if dss.Solution.Mode() in (dss_py.enums.SolveModes.Harmonic, 17):
+        # Note: Mode 17 is HarmonicT but it was not exposed in the enum
+        #       ported from COM as of 2021-01-03
+        columns = ['frequency', 'harmonic'] 
+    else:
+        columns = ['hour', 'second'] 
+
+    columns.extend(col.strip() for col in dss.Monitors.Header())
+    data = dss.Monitors.AsMatrix()
+
+    if is_pandas_installed:
+        return pd.DataFrame(data, columns=columns)
+    else:
+        warnings.warn(
+            "Pandas is not installed. Please see documentation for how to install extra dependencies."
+        )
+        return dict(zip(columns, data.T))
+
+
 def monitors_to_dataframe(dss=None):
     if dss is None:
         import opendssdirect as dss

tests/test_opendssdirect.py

@@ -1963,6 +1963,56 @@ def test_13Node_Monitors(dss):
     assert dss.Monitors.ResetAll() is None
     assert dss.Monitors.SaveAll() is None
     assert dss.Monitors.SampleAll() is None
+    
+    dss.Text.Command("new monitor.test_monitor element=Transformer.Reg3 terminal=2 mode=2")
+    dss.Text.Command("solve mode=daily step=15m number=10")
+    
+    assert dss.Monitors.Count() == 1
+    assert dss.Monitors.First() == 1
+    
+    expected_dict = pd.DataFrame(
+        {
+            "Tap (pu)": {
+                0: 1.056249976158142,
+                1: 1.056249976158142,
+                2: 1.056249976158142,
+                3: 1.056249976158142,
+                4: 1.056249976158142,
+                5: 1.056249976158142,
+                6: 1.056249976158142,
+                7: 1.056249976158142,
+                8: 1.056249976158142,
+                9: 1.056249976158142
+            },
+            "hour": {
+                0: 0.0,
+                1: 0.0,
+                2: 0.0,
+                3: 1.0,
+                4: 1.0,
+                5: 1.0,
+                6: 1.0,
+                7: 2.0,
+                8: 2.0,
+                9: 2.0
+            },
+            "second": {
+                0: 900.0,
+                1: 1800.0,
+                2: 2700.0,
+                3: 0.0,
+                4: 900.0,
+                5: 1800.0,
+                6: 2700.0,
+                7: 0.0,
+                8: 900.0,
+                9: 1800.0
+            }
+        }
+    ).to_dict()
+
+    actual_dict = dss.utils.monitor_to_dataframe().to_dict()
+    assert_dict_equal(actual_dict, expected_dict)
 
 
 def test_13Node_PDElements(dss):