How can I show some values(these values changes continuously) in a box?

Dash Python
1

can any help me how to do this??

Thanks in advance.

2

The box can be a html.Div which you target as the output of a callback. The callback would retrieve the values and display them. The callback could be triggered either by values changing if they are coming from the frontend, or by a dcc.Interval if you want to periodically update the values. See https://dash.plot.ly/live-updates for more on that.

3

Hi @bhanu8 - I wonder if this is the same question you sent a DM about - it’s better to keep these discussions public so everyone can help (and benefit from the answers) so I’ll re-ask and answer it here, since it looks similar. The DM:

hey hi this is bhanu can you please help me how to create a list box which will read my excel data and just show in that list box and when the data changes then the list box should get updated .

I would approach this problem something like this:

  • Create a dcc.Interval component to check for updates, a dcc.Store component with storage_type='local' to hold the modification time of the file, and a dcc.Dropdown to hold your results.
  • Make a callback that takes the interval’s n_intervals prop as Input and the store’s data as State, and returns both the dropdown’s options and the store’s data as Output.
  • In that callback, first check the modification time of the file - if it’s the same as the store data, raise dash.exceptions.PreventUpdate. Otherwise, read your excel file and convert it to options, then return both the options and the modification time for the store’s data.

Hope that helps!

4

Thanks for your reply, but Alex I don’t need a dropdown I need a normal list box which just print the cells of my excel in the box.

5

OK, so don’t make a Dropdown to hold the results, perhaps a dash_table.DataTable, or dcc.Checklist or dcc.RadioItems?

You can make any HTML elements you want, so if you really want a traditional list box you can do it, make a html.Div element and have the callback connect to its children prop, and return something like

html.Select([html.Option(v) for v in values], size=20)

(assuming you’ve read your excel file into a values list). Be aware though that we have not created event handlers for html.Select, so you wouldn’t be able to read back out the items the user chooses. If you need that, I’d suggest one of the options above.