implemented feature

skais/ais/ais_trajectory.py

@@ -215,5 +215,11 @@ class AISTrajectory(AISPoints):
         else:
             return AISTrajectory(new_df, mmsi=self.mmsi)
 
-    def get_time_per_label_shift(self):
-        pass
\ No newline at end of file
+    def get_time_per_label_shift(self, label_column='label'):
+        current_label = -1
+        result = []
+        for index, row in self.df.iterrows():
+            if current_label != row[label_column]:
+                current_label = row[label_column]
+                result.append((row['ts_sec'], current_label))
+        return result
\ No newline at end of file

skais/tests/ais/test_ais_trajectory.py

@@ -354,7 +354,7 @@ class TestAISTrajectory(unittest.TestCase):
         trajectory = AISTrajectory(
             pd.DataFrame(
                 {
-                    "label": [1 for _ in range(0, 101, 10)] + [2 for _ in range(0, 101, 10)],
+                    "label": [1 for _ in range(11)] + [2 for _ in range(10)],
                     "ts_sec": [i for i in range(0, 12001, 600)]
                 }
             )
@@ -369,7 +369,7 @@ class TestAISTrajectory(unittest.TestCase):
         trajectory = AISTrajectory(
             pd.DataFrame(
                 {
-                    "label": [1 for _ in range(0, 101, 10)] + [2 for _ in range(0, 101, 10)]+ [1 for _ in range(0, 101, 10)],
+                    "label": [1 for _ in range(11)] + [2 for _ in range(10)]+ [1 for _ in range(10)],
                     "ts_sec": [i for i in range(0, 18001, 600)]
                 }
             )