Clicking a button clears the other button's output

🎈 Using Streamlit
1

Summary

I want to run 4 models in the same page by clicking 4 different buttons for each one.

When I click the first button, the first model is applied and I have an output.
When I click the second button, the output of the first model disappears.

I tried by saving in the memory the output and re-print it. I tried using session_state. I tried using Parallelize.
But nothing worked

Steps to reproduce

Code snippet:

if uploaded_file is not None:
    
    image = Image.open(uploaded_file)
    st.sidebar.image(image, caption='Input Image', use_column_width= 'auto')

    if st.button('Predict 1'):
        st.write('## Model 2')
        model2(image) #this is gonna show a plot

    if st.button('Predict 2'):
        st.write('## Model 2')        
        st.write(model3(image))#this is gonna show a text
          
    if st.button('Predict 3'):        
        st.write('## Model 3 ')

        st.write(model3(image)) #this is gonna show a text

    if st.button('Predict 4'):
        st.write('## Model 4')

        st.write(model4(image)) #this is gonna show a text

Expected behavior:

I expected the buttons to “leave untouched” the different outputs

Actual behavior:

If I click any button, I clear every other button’s output

2

Hey @fr3nz99, can you share the example where you tried implementing this with session state? As is, I would expect the output to clear since the Streamlit reruns your script when you interact with a widget.

3

There might be a cleaner way to do this, but I would create 4 session_state variables that track whether a model has been run:

if "model1_computed" not in st.session_state:
    st.session_state.model1_computed = False
if "model2_computed" not in st.session_state:
    st.session_state.model2_computed = False
if "model3_computed" not in st.session_state:
    st.session_state.model3_computed = False
if "model4_computed" not in st.session_state:
    st.session_state.model4_computed = False

if uploaded_file is not None:
    
    image = Image.open(uploaded_file)
    st.sidebar.image(image, caption='Input Image', use_column_width= 'auto')

    if st.button("Predict 1") or st.session_state.model1_computed:
        st.write("## Model 1")
        model2(image) #this is gonna show a plot
        st.session_state.model1_computed = True

    if st.button("Predict 2") or  st.session_state.model2_computed:
        st.write("## Model 2")        
        st.write(model3(image))#this is gonna show a text
        st.session_state.model2_computed = True
          
    if st.button("Predict 3") or  st.session_state.model3_computed:        
        st.write("## Model 3 ")
        st.write(model3(image)) #this is gonna show a text
        st.session_state.model3_computed = True

    if st.button("Predict 4") or  st.session_state.model4_computed:
        st.write("## Model 4")
        st.write(model4(image)) #this is gonna show a text
        st.session_state.model4_computed = True

However, it looks as though your code will re-run each model each time you want to run a new one, especially if you apply the above, wasting computational power. I would consider changing what your model1 - model4 functions return or do, so that you could save the outputs of your model to the session state, and you don’t need to re-compute the functions/models each time. Something like:

if "model1_computed" not in st.session_state:
    st.session_state.model1_computed = False

if uploaded_file is not None:
    
    image = Image.open(uploaded_file)
    st.sidebar.image(image, caption='Input Image', use_column_width= 'auto')

    if st.button("Predict 1"):
        #Compute the model, store in session state, set 'computed' indicator to True
        st.session_state.model1_output = model1(image) #This saves the model outputs into the session_state
        st.session_state.model1_computed = True
    #etc etc for other models

# Check to see if models were run, and display output if it was:
if st.session_state.model1_computed:
    st.write("## Model 1")
    st.write(st.session_state.model1_output)
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