This is now possible in the latest Streamlit release, with the st.beta_columns feature!
left, right = st.beta_columns(2)
with left:
st.subheader('Unique Item Types :')
with right:
if (st.checkbox("bar chart", key='chk_Unique_item')):
st.bar_chart(list_of_item_type(df))
else:
st.dataframe(list_of_item_type(df))