Initialize session state not working

Using Streamlit
,
1

Summary

I am trying to run this simple code to test the session state, but every time I run it I get the same error (see below). I have read already about several issues like this, but the solutions do not suit to me

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File “c:\Users\thomas\Desktop\python_codes\regenschreiber_frontend\teste_render.py”, line 12, in
st.write('Count = ', st.session_state.count)
File “C:\Users\thomas\AppData\Roaming\Python\Python310\site-packages\streamlit\runtime\state\session_state_proxy.py”, line 121, in getattr
raise AttributeError(_missing_attr_error_message(key))
AttributeError: st.session_state has no attribute “count”. Did you forget to initialize it? More info: Add statefulness to apps - Streamlit Docs

Steps to reproduce

Code snippet:

import streamlit as st

st.title("Counter Example")

if "count" not in st.session_state:
    st.session_state.count = 0

increment = st.button("Increment")
if increment:
    st.session_state.count += 1

st.write('Count = ', st.session_state.count)

Expected behavior:

I expect that session state would be initialized

Actual behavior:

Session state not initialized

Debug info

  • Streamlit version: 1.31.0
  • Python version: 3.10.11
  • Using Conda? Conda, PipEnv
  • OS version: Windows
  • Browser version: Firefox

Requirements file

streamlit==1.31.0

2

Hi @bruno_castro93

Using the if conditional with st.button would allow showing a temporary message that may be reset upon click.

In your case, you may want to use a callback function via the on_click parameter with st.button

Consider the following code snippet example from Button behavior and examples - Streamlit Docs

import streamlit as st

if ‘clicked’ not in st.session_state:
st.session_state.clicked = False

def click_button():
st.session_state.clicked = True

st.button(‘Click me’, on_click=click_button)

if st.session_state.clicked:
# The message and nested widget will remain on the page
st.write(‘Button clicked!’)
st.slider(‘Select a value’)

3

Thank you for the fast reply, but even with your code, the app does not initialize. See the error below:

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File “c:\Users\thomas\Desktop\python_codes\regenschreiber_frontend\session.py”, line 11, in
if st.session_state.clicked:
File “C:\Users\thomas\AppData\Roaming\Python\Python310\site-packages\streamlit\runtime\state\session_state_proxy.py”, line 121, in getattr
raise AttributeError(_missing_attr_error_message(key))
AttributeError: st.session_state has no attribute “clicked”. Did you forget to initialize it? More info: Add statefulness to apps - Streamlit Docs
PS C:\Users\thomas\Desktop\python_codes\regenschreiber_frontend>

4

What do you mean by that? Your code seems to work for me. Count = 0 appears and clicking the button increases the counter.

5

I mean, I get this message in my terminal and the app does not run

AttributeError: st.session_state has no attribute “clicked”. Did you forget to initialize it? More info: Add statefulness to apps - Streamlit Docs

6

That is weird. I copied ans pasted your code and it just works here.

¿Can you reproduce the issue in streamlit cloud?

7

the app works in the streamlit cloud, but it does not work locally :frowning:

8

I have no idea why this happens. The code in the OP is as good as it goes, the problem must lie somewhere else.

9

I had the same issue - but after going bonkers for a few mins I realized I was trying to run it as a regular python script (python streamlit_app.py) instead of streamlit run streamlit_app.py