Iâd like to add a feature to my streamlit app where a list ends with a âShow moreâ button, and pressing the button queries for more data, and puts the âShow moreâ button at the end of the extended list. Exactly like how google scholar implements it: https://scholar.google.com/citations?user=JicYPdAAAAAJ&hl=en&oi=ao
import random
import time
import streamlit as st
import SessionState
@st.cache
def long_calculation(i):
time.sleep(1)
return 1000 * i + random.randrange(100)
def main():
session_state = SessionState.get(length=5)
if st.button("Show more"):
session_state.length += 5
for i in range(1, session_state.length + 1):
st.write("item %d: %d" % (i, long_calculation(i)))
main()
The only difference between this and my imagined ideal solution is that here the âShow moreâ button is at the beginning, not at the end where it should be. Unfortunately this is extremely bad UX for long lists, and Iâm stuck here. Is there a way to fix this issue, either along these lines, or starting from scratch?
If Iâm correctly understanding what youâre after, you can accomplish this with some minor abuse of RerunException (which is currently undocumented and subject to change):
from streamlit.ScriptRequestQueue import RerunData
from streamlit.ScriptRunner import RerunException
def main():
session_state = SessionState.get(length=5)
for i in range(1, session_state.length + 1):
st.write("item %d: %d" % (i, long_calculation(i)))
if st.button("Show more"):
session_state.length += 5
# Force an immediate rerun of the report. This is a bit
# ugly, but it ensures that the report will be rerun
# *after* session state gets updated.
raise RerunException(RerunData(widget_state=None))
Hopefully, when SessionState becomes a proper Streamlit citizen, simply modifying it will be enough to trigger a rerun, and these gymnastics wonât be necessary!
I like this expand content idea, what would be nice if a component like st.markdown which has content which is easily truncated had an option like st.markdown(txt, show_lines=5), so it only displays the first few lines and puts in a expand icon to show all the text.
Useful for things like putting in a block of explainer text for different objects. And other uses, like showing the head/tail of a log with an expand option to show all the log.
Itâs currently being tracked in this Github issue . I donât know thereâs a fixed timeline decided for this feature yet, but itâs being discussed and I think weâll be working on it in earnest soon!
I am using the current version. Thereâs no error or traceback, but the script behaves in a weird way. For each click it does the long calculations, appends the results at the end as it is supposed to, but then removes everything, restarts the calculations, and only does it for the first five items. So it re-runs twice for each button-click, and the second rerun destroys the results of the first rerun. I am not sure if Iâm using st.SessionState() right:
import streamlit as st
import st_state_patch
from streamlit.ScriptRequestQueue import RerunData
from streamlit.ScriptRunner import RerunException
import time
def long_calculation(x):
time.sleep(1)
return 10 * x
def main():
session_state = st.SessionState()
if not session_state:
session_state.length = 5
for i in range(1, session_state.length + 1):
st.write("item %d: %d" % (i, long_calculation(i)))
if st.button("Show more"):
session_state.length += 5
# Force an immediate rerun of the report. This is a bit
# ugly, but it ensures that the report will be rerun
# *after* session state gets updated.
raise RerunException(RerunData(widget_state=None))
main()
import streamlit as st
from state import get
from streamlit.ScriptRequestQueue import RerunData
from streamlit.ScriptRunner import RerunException
import time
def long_calculation(x):
time.sleep(0.1)
return 10 * x
session_state = get(length=5)
for i in range(1, session_state.length + 1):
st.write("item %d: %d" % (i, long_calculation(i)))
if st.button("Show more"):
session_state.length += 5
raise RerunException(RerunData(widget_state=None))
And state.py below
"""Hack to add per-session state to Streamlit.
Usage
-----
>>> import SessionState
>>>
>>> session_state = SessionState.get(user_name='', favorite_color='black')
>>> session_state.user_name
''
>>> session_state.user_name = 'Mary'
>>> session_state.favorite_color
'black'
Since you set user_name above, next time your script runs this will be the
result:
>>> session_state = get(user_name='', favorite_color='black')
>>> session_state.user_name
'Mary'
"""
import streamlit.ReportThread as ReportThread
from streamlit.server.Server import Server
class SessionState(object):
def __init__(self, **kwargs):
"""A new SessionState object.
Parameters
----------
**kwargs : any
Default values for the session state.
Example
-------
>>> session_state = SessionState(user_name='', favorite_color='black')
>>> session_state.user_name = 'Mary'
''
>>> session_state.favorite_color
'black'
"""
for key, val in kwargs.items():
setattr(self, key, val)
def get(**kwargs):
"""Gets a SessionState object for the current session.
Creates a new object if necessary.
Parameters
----------
**kwargs : any
Default values you want to add to the session state, if we're creating a
new one.
Example
-------
>>> session_state = get(user_name='', favorite_color='black')
>>> session_state.user_name
''
>>> session_state.user_name = 'Mary'
>>> session_state.favorite_color
'black'
Since you set user_name above, next time your script runs this will be the
result:
>>> session_state = get(user_name='', favorite_color='black')
>>> session_state.user_name
'Mary'
"""
# Hack to get the session object from Streamlit.
ctx = ReportThread.get_report_ctx()
this_session = None
current_server = Server.get_current()
if hasattr(current_server, '_session_infos'):
# Streamlit < 0.56
session_infos = Server.get_current()._session_infos.values()
else:
session_infos = Server.get_current()._session_info_by_id.values()
for session_info in session_infos:
s = session_info.session
if (
# Streamlit < 0.54.0
(hasattr(s, '_main_dg') and s._main_dg == ctx.main_dg)
or
# Streamlit >= 0.54.0
(not hasattr(s, '_main_dg') and s.enqueue == ctx.enqueue)
):
this_session = s
if this_session is None:
raise RuntimeError(
"Oh noes. Couldn't get your Streamlit Session object"
'Are you doing something fancy with threads?')
# Got the session object! Now let's attach some state into it.
if not hasattr(this_session, '_custom_session_state'):
this_session._custom_session_state = SessionState(**kwargs)
return this_session._custom_session_state
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