Hi, I'm trying to create dynamic pages, but there's hiccup. Each time I select a value from the drop down list the whole session re-runs and the subsequent page does not load. Let me break it down.

1. I'm taking a number as an input n.
   

2. On clicking next it creates n modules and adds them to the list.
   

3. But when I select, say Member 2 from the list, the session re-runs and I'm left with the first image 👆🏻. The page against Member 2 does not load.

app.py

f_name = st.sidebar.text_input("Family Name")
number_of_members = st.sidebar.number_input(
    label="Enter number of family members: ", key="mem_num", min_value=1, max_value=20)

nxt_btn = st.sidebar.button("Next")

if nxt_btn:
    modules = []
    app = MultiApp()

    recreate(pages_path=dst_dir)
    for idx in range(number_of_members):
        shutil.copy(src=src_dir + "/memberX.py",
                    dst=dst_dir + f"/member{idx+1}.py")
        try:
            modules.append(importlib.import_module(
                name=f"pages.member{idx+1}"))
        except ModuleNotFoundError:
            logger.error(f"Abort! Module {idx+1} not found!")

        app.add_app(f"Member {idx+1}", modules[idx].app)

    # The main app
    app.run()

multiapp.py

import streamlit as st


class MultiApp:
    def __init__(self):
        self.all_apps = []

    def add_app(self, title, func):
        self.all_apps.append({
            "title": title,
            "function": func
        })

    def run(self):
        app = st.sidebar.selectbox(
            'Navigation',
            self.all_apps,
            format_func=lambda app: app['title'])
        app['function']()

Can you please show me where am I going wrong?

A bug that happened occaisionally in multiapp.py gave error in widgets.py

widgets.py", line 148, in register_widget
    raise DuplicateWidgetID(
streamlit.errors.DuplicateWidgetID: There are multiple identical `st.selectbox` widgets with the
same generated key.

Solved it by importing random and adding key=str(random.getrandbits(32)) as shown below.

    def run(self): # test
        count = 0
        count += 1
        app = st.sidebar.selectbox(
            'Navigation',
            self.apps,
            format_func=lambda app: app['title'],
            key=str(random.getrandbits(32))
        )

the above makes the navbar unusable so I'm still stuck with

I tried to find out how to reproduce but it seemed to happen randomly when autorun on save was on so I'll leave that to another if they get the same thing

/streamlit/util.py", line 129, in index_
    raise ValueError("{} is not in iterable".format(str(x)))
ValueError: {'title': 'Test', 'function': <function app at 0x7f46984b0310>} is not in iterable

Which only occurs after saving a file then rerunning the page

The issue is the lambda function:

            format_func=lambda app: app['title']

When you save the file and update the page, each "app" is re-saved as a new object file within python (like an instance)

The lambda function looks for the previous object instance instead of the one updated in self.apps. I've no idea how to fix this