Fix channel reordering

Author: cimbi

src/dhn_med_py/med_session.py

@@ -722,9 +722,8 @@ def read_by_time(self, start_time, end_time, channels=None):
 
             # Make sure the data is in requested channels order
             if type(channels) is list:
-                channel_indices = [channel_names.index(x) for x in channels]
-                reordered_pos = sorted(range(len(channel_indices)), key=lambda x: channel_indices[x])
-                data = [data[i] for i in reordered_pos]
+                channel_indices = [channel_names.index(ch) for ch in channels]
+                data = [data[i] for i in channel_indices]
 
             self.set_channel_active(channel_names, False)
             self.set_channel_active(curr_active_channels, True)
@@ -801,9 +800,8 @@ def read_by_index(self, start_idx, end_idx, channels=None):
 
             # Make sure the data is in requested channels order
             if type(channels) is list:
-                channel_indices = [channel_names.index(x) for x in channels]
-                reordered_pos = sorted(range(len(channel_indices)), key=lambda x: channel_indices[x])
-                data = [data[i] for i in reordered_pos]
+                channel_indices = [channel_names.index(ch) for ch in channels]
+                data = [data[i] for i in channel_indices]
 
             self.set_channel_active(channel_names, False)
             self.set_channel_active(curr_active_channels, True)

test/dhn_med_py_test.py

@@ -19,7 +19,7 @@
 """
 
 # Standard library imports
-import unittest
+import unittest, random
 
 # Third party imports
 import numpy as np
@@ -261,12 +261,16 @@ def test_read_session(self):
         assert len(data) == len(channel_names)
         assert len(data[ref_index]) == int(10 * chan_fs)
 
-        # Read by index reverted order channels specified
-        rev_data = ms.read_by_index(0, int(10*chan_fs), channel_names[::-1])
+        # Read by index mixed order channels specified
+        mixed_order = channel_names.copy()
+        random.shuffle(mixed_order)
+
+        rev_data = ms.read_by_index(0, int(10*chan_fs), mixed_order)
 
         assert len(rev_data) == len(channel_names)
-        assert len(rev_data[-1]) == len(data[0])
-        np.testing.assert_array_equal(rev_data[-1], data[0])
+        for i, ch in enumerate(mixed_order):
+            ch_idx = channel_names.index(ch)
+            np.testing.assert_array_equal(rev_data[i], data[ch_idx])
 
         # Read by index - no channels specified
         data = ms.read_by_index(0, int(10*chan_fs), None)
@@ -302,12 +306,16 @@ def test_read_session(self):
         assert len(data) == len(channel_names)
         assert len(data[ref_index]) == int(10 * ref_fs) + 5 # TODO: why +5?
 
-        # Read by time reverted order channels specified
-        rev_data = ms.read_by_time(start_time, start_time + 10 * 1000000, channel_names[::-1])
+        # Read by time mixed order channels specified
+        mixed_order = channel_names.copy()
+        random.shuffle(mixed_order)
+
+        rev_data = ms.read_by_time(start_time, start_time + 10 * 1000000, mixed_order)
 
         assert len(rev_data) == len(channel_names)
-        assert len(rev_data[-1]) == len(data[0])
-        np.testing.assert_array_equal(rev_data[-1], data[0])
+        for i, ch in enumerate(mixed_order):
+            ch_idx = channel_names.index(ch)
+            np.testing.assert_array_equal(rev_data[i], data[ch_idx])
 
         # Read by time - no channels specified
         data = ms.read_by_time(start_time, start_time + 10 * 1000000)