app.py

import streamlit as st
import pandas as pd

astations = [
	["hongkongobservatory","HKO",22.3022566,114.1722662,"Hong Kong Observatory"],
	["kingspark","KP",22.3115408,114.1685675,"Observatory Meteorological Station, King's Park"],
]
astationcolumns = ['akey','astationcode','alatitude','alongitude','atitle',]

acontainer1 = st.empty()
acontainer2 = st.empty()
acontainer3 = st.empty()

def asubmit(aparam):
	adf2 = aparam["adataframe"]
	aselecteditem = adf2[adf2.loc[adf2["atitle"]==aparam["aselected"]]]["astationcode"]
	aparam["acontainer"].write((" {} ").format(aselecteditem))

adf = pd.DataFrame(
	astations,
	columns=astationcolumns
)
aoption = acontainer1.selectbox(
	'Which station?',
	adf['atitle']
)
if acontainer2.button("Submit") == True:
	asubmit(aparam={"aselected":aoption,"acontainer":acontainer3,"adataframe":adf,})