When multiple users access the same window (@ui.page("/")), any user's modification to the rows of ui.table() will only take effect in the ​​window accessed by the last user​​.

[SHDocter]

First Check

• I added a very descriptive title here.
• I have checked the FAQs for a similar question and didn't find it.
• I used the GitHub search to find a similar question and didn't find it.
• I searched the NiceGUI documentation, with the integrated search.
• I already searched online "How to X in NiceGUI" and didn't find any information.

Example Code

from nicegui import ui

def change(key):
    rows = {
        "a": [{"name": "Aa", "artist": "Artist A"},
                {"name": "Ab", "artist": "Artist A"}],
        "b": [{"name": "Ba", "artist": "Artist B"},
                {"name": "Bb", "artist": "Artist B"}],
        "c": [{"name": "Ca", "artist": "Artist C"},
                {"name": "Cb", "artist": "Artist C"}]
    }

    table.rows = rows[key]

@ui.page("/")
def index():
    global table
    columns = [
    {'name': 'name', 'label': 'song_name', 'field': 'name', 'align': 'center'},
    {'name': 'artist', 'label': 'song_artist', 'field': 'artist', 'align': 'center'}
]

    table = ui.table(columns=columns, rows=[{"name": None, "artist": None}])
    ui.input(on_change=lambda e: change(e.value))

ui.run()

Description

I think the problem seems to be with the global table, but change() is called in many places and it seems unlikely to move it into index().

When change() is in index(), everything works fine, but once it is moved out, this problem arises.

If I manually pass the parameter table=table (like: ui.input(on_change=lambda e: change(e.value, table = table))), it also looks to work well. (Sure, def change(key, table):

NiceGUI Version

2.20.0

Python Version

3.13.5

Browser

Edge, Firefox

Operating System

Windows

Additional Context

No response

[falkoschindler]

Hi @SHDocter,

With every call to index you're overwriting the global table variable. So when you update the rows in change, you're only affecting the table which has been created last.

Instead of keeping track of a single table only, you can try keeping a weak set of tables and iterate over them to update their rows. Using a WeakSet avoids keeping strong references which would cause a memory leak.

from weakref import WeakSet
from nicegui import ui

tables: WeakSet[ui.table] = WeakSet()

def change(key):
    for table in tables:
        table.rows = {
            'a': [{'name': 'Aa', 'artist': 'Artist A'}, {'name': 'Ab', 'artist': 'Artist A'}],
            'b': [{'name': 'Ba', 'artist': 'Artist B'}, {'name': 'Bb', 'artist': 'Artist B'}],
            'c': [{'name': 'Ca', 'artist': 'Artist C'}, {'name': 'Cb', 'artist': 'Artist C'}],
        }[key]

@ui.page('/')
def index():
    table = ui.table(columns=[
        {'name': 'name', 'label': 'song_name', 'field': 'name', 'align': 'center'},
        {'name': 'artist', 'label': 'song_artist', 'field': 'artist', 'align': 'center'}
    ], rows=[{'name': None, 'artist': None}])
    tables.add(table)
    ui.input(on_change=lambda e: change(e.value))

ui.run()

To prove that no tables are held in memory after closing browser tabs, you can count then with an app.timer after garbage collection. Simply put this line in global scope:

app.timer(0.5, lambda: (gc.collect(), print(f'tables: {len(tables)}')))

[SHDocter]

Thanks! I'm very sorry for the late reply, but i don't want to modify all tables, and I don't want one user's modifications to affect other users.

If I manually pass the parameter table=table (like: ui.input(on_change=lambda e: change(e.value, table = table)))

Can I use this usage? Is there any question I don't know?

[falkoschindler]

Sure. If you don't need a global reference, you can simply pass the current instance to the change handler:

def change(key, table):
    table.rows = {
        'a': [{'name': 'Aa', 'artist': 'Artist A'}, {'name': 'Ab', 'artist': 'Artist A'}],
        'b': [{'name': 'Ba', 'artist': 'Artist B'}, {'name': 'Bb', 'artist': 'Artist B'}],
        'c': [{'name': 'Ca', 'artist': 'Artist C'}, {'name': 'Cb', 'artist': 'Artist C'}]
    }[key]

@ui.page('/')
def index():
    table = ui.table(columns=[
        {'name': 'name', 'label': 'song_name', 'field': 'name', 'align': 'center'},
        {'name': 'artist', 'label': 'song_artist', 'field': 'artist', 'align': 'center'}
    ], rows=[{'name': None, 'artist': None}])
    ui.input(on_change=lambda e, table=table: change(e.value, table))