add total collection period display

app.py

@@ -14,7 +14,12 @@ def load_data():
     for name in dataset_names:
         print("Loading dataset: ", name)
         all_datasets[name] = pd.DataFrame(datasets.load_dataset("cyberorigin/"+name)['train'])
-    return all_datasets
+    total_period = 0
+    for dataset in all_datasets.values():
+        # dataset["timestamp"] = dataset["timestamp"].astype(float)
+        traj_period = dataset["timestamp"].iloc[-1] - dataset["timestamp"].iloc[0]
+        total_period += traj_period
+    return all_datasets, total_period
 
 @st.fragment
 def visualize(data):
@@ -137,5 +142,7 @@ def visualize(data):
 
 
 st.title("CyberOrigin Data Visualization")
-data = load_data()
+data, period = load_data()
+# display the total period of the data up to 2 decimal places
+st.write("Total period of data: ", round(period, 2), " seconds")
 visualize(data)