Update app.py

app.py

@@ -38,6 +38,27 @@ def factorial(n):
 #em09 = factorial(9)  # Returns instantly!
 #print("em09:",em09)
 
+
+# callback to update query param on selectbox change
+def update_params():
+    st.experimental_set_query_params(option=st.session_state.qp)
+options = ["cat", "dog", "mouse", "bat", "duck"]
+query_params = st.experimental_get_query_params()
+# set selectbox value based on query param, or provide a default
+ix = 0
+if query_params:
+    try:
+        ix = options.index(query_params['option'][0])
+    except ValueError:
+        pass
+selected_option = st.radio(
+    "Param", options, index=ix, key="qp", on_change=update_params
+)
+# set query param based on selection
+st.experimental_set_query_params(option=selected_option)
+
+
+
 DEVICE = "cpu"
 MODEL_OPTIONS = ["msmarco-distilbert-base-tas-b", "all-mpnet-base-v2"]
 DESCRIPTION = """