How to add custom buttons to update data in plotly graph

đź“Š Plotly Python
1

Hi,
I find plotly library is a veary goof library. I’m trying to build a graph like this one below, I’m just wandring if I can add custom buttons to refresh data on the graph.

for examle if I click the right arrow button I need to get the next six months (if exist) and when I click the left arrow button I need to get back the last six month (if exist). is this possible with plotly library please ?

image
image724Ă—362 32.3 KB

thanks for your help.

2

HI @Youp,

Sorry, not sure I understand - do you want to know how to add buttons underneath the graph; or how to make the buttons change what’s displayed; or both?

  • To add buttons underneath, you can use the html.Button component, with some custom styling.
  • You could also use other libraries like Dash Bootstrap Components and Dash Mantine Components to help with the placement of the buttons and for nicer out-of-the-box styling.
  • To update the graph when buttons are clicked; you’d need to add a callback to each of the buttons. E.g. the left arrow button would filter the original data to just have the previous 6 months; the right arrow button would filter the data to just have the next 6 months.

I realise that’s a bit general - I can provide more detail as needed.

3

thanks for your time and effort.

  • do you want to know how to add buttons underneath the graph; or how to make the buttons change what’s displayed; or both?
  • => I want both, Could you please provide an example how I can combine plotly graph with [html.Button] ?
  • thanks
4

A bare-bones example of something that (I think) does what you’re describing:

# -------------------------------------------------------------------------------------------------
# Imports
# -------------------------------------------------------------------------------------------------
from dash import Dash, html, dcc, Input, Output, callback, ctx
import plotly.express as px
import pandas as pd
import numpy as np


# -------------------------------------------------------------------------------------------------
# App setup
# -------------------------------------------------------------------------------------------------
app = Dash()

# create some random time-series data, daily from 01-Jun-2024 to 31-Jul-2025
dates = pd.date_range(start="6/1/2024", end="07/31/2025")
values = np.random.default_rng().uniform(1, 10, len(dates))
df = pd.DataFrame({"dates": dates, "values": values})

# create a line graph of the data
fig = px.line(df, x="dates", y="values")

# set up the app layout
app.layout = html.Div(
    children=[
        # Header
        html.H1(children="Hello Dash"),

        # Time series line graph
        dcc.Graph(id="time-series-graph", figure=fig),

        # 2 x buttons: see https://dash.plotly.com/dash-html-components/button
        html.Div(
            [
                html.Button("Left", id="left-btn", n_clicks=0),
                html.Button("Right", id="right-btn", n_clicks=0)
            ]
        )
    ]
)

# -------------------------------------------------------------------------------------------------
# Callbacks to update the graph, see:
# - https://dash.plotly.com/basic-callbacks
# - https://dash.plotly.com/duplicate-callback-outputs
# -------------------------------------------------------------------------------------------------
@callback(
    Output("time-series-graph", "figure"),
    Input("left-btn", "n_clicks"),
    Input("right-btn", "n_clicks"),
    prevent_initial_call=True   # we don't want the callback to fire when the app loads initially
)
def update_graph(left_clicks, right_clicks):
    # The line below works out whether left-btn or right-btn was clicked to trigger the callback.
    # [Needs proper date filtering based on 'now' +/- 6 months; below is just a hack to illustate]
    triggered_id = ctx.triggered_id
    if triggered_id == "left-btn":
        ddf = df[df["dates"] < "2024-12-31"]
    elif triggered_id == "right-btn":
        ddf = df[df["dates"] > "2025-01-17"]

    return px.line(ddf, x="dates", y="values")


if __name__ == "__main__":
    app.run(debug=True)

I’ve only used standard Plotly here, not Dash Bootstrap Components or Dash Mantine Components, but they’ll work in a similar way.

The date filtering in the callback is just a very simple hack; you’ll need to add proper logic. But should help put you on the right path.

5

thanks for your time and effort…I tried to run this code to see how it looks the result but it gives me this error :

line 66, in 
    app.run(debug=True)
  File "/lib/python3.12/site-packages/dash/dash.py", line 2098, in run
    debug = self.enable_dev_tools(
            ^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/dash/dash.py", line 1864, in enable_dev_tools
    _reload.watch_thread.start()
  File "/lib/python312.zip/threading.py", line 992, in start
    _start_new_thread(self._bootstrap, ())
RuntimeError: can't start new thread

I have tried this link to test : https://python-fiddle.com/examples/plotly?checkpoint=1737454305

Could you help please ?

6

When I run the fiddle in your link, I don’t get any errors?

image
image942Ă—693 20.2 KB

It does say “you have unsaved changes” though - maybe that checkpoint isn’t up to date?