由 neevop 十二月 3, 2023
st.session_state
import streamlit as st
# Initialization
if 'key' not in st.session_state:
st.session_state['key'] = 'value'
# Session State also supports attribute based syntax
if 'key' not in st.session_state:
st.session_state.key = 'value'
st.write(st.session_state.key)
st.session_state.key = 'value2' # Attribute API
st.session_state['key'] = 'value2' # Dictionary like API
st.session_state
st.write(st.session_state['value2'])
每个带有键的小部件都会自动添加到会话状态：
st.text_input("Your name", key="name")
# This exists now:
st.session_state.name
回调
回调是一个 Python 函数，当输入小部件发生更改时会调用该函数。当响应事件更新Session状态时，首先执行回调函数，然后从上到下执行应用程序。on_change并且on_click事件仅在输入类型小部件上受支持。
def form_callback():
st.write(st.session_state.my_slider)
st.write(st.session_state.my_checkbox)
# 只有st.form_submit_button表单中有回调。表单内的其他小部件不允许有回调。
with st.form(key='my_form'):
slider_input = st.slider('My slider', 0, 10, 5, key='my_slider')
checkbox_input = st.checkbox('Yes or No', key='my_checkbox')
submit_button = st.form_submit_button(label='Submit', on_click=form_callback)
st.set_page_config
配置页面的默认设置，并且每个页面只能设置一次。
# st.set_page_config(page_title=None, page_icon=None, layout="centered", initial_sidebar_state="auto", menu_items=None)
import streamlit as st
st.set_page_config(
page_title="Ex-stream-ly Cool App",
page_icon="🧊",
layout="wide",
initial_sidebar_state="expanded",
menu_items={
'Get Help': 'https://www.extremelycoolapp.com/help',
'Report a bug': "https://www.extremelycoolapp.com/bug",
'About': "# This is a header. This is an *extremely* cool app!"
}
)