Hi, I would like to use hoverData and clickData from a plot to highlight certain rows in a DataTable WITHOUT RELOADING the datatable. It should work all on the front end to avoid performance issues. Does anybody know how to do it?
Thank you very much.
Itâs possible to update just the style properties of the table (ie style_cell, style_data etc) in a callback. This should update the style without reloading all of the data.
Let me know if you would like more details or an example.
Hi @AnnMarieW thank you very much. I would really appreciated any details or an example. 
And I forgot to mention one thing: When I click on a datapoint in the plot it should not only highlight the respective row in the DataTable but also automatically show the row i.e. it should âautomatically scroll to this rowâ. I hope I am asking not too much. Thanks.
Well, Iâm not sure how to automatically scroll to a row in a table, but this code uses a sunburst chart to do a drill down on a table with clickdata, and highlights data on hover. It will at least give you an idea of how to update style based on hover or click data.
import dash
import dash_table
from dash.dependencies import Input, Output
import dash_core_components as dcc
import dash_html_components as html
import plotly.express as px
external_stylesheets = ["https://codepen.io/chriddyp/pen/bWLwgP.css"]
app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
df = px.data.tips()
path = ["day", "time", "sex"]
app.layout = html.Div(
[
html.H4(id="title"),
html.Div(
[
dcc.Graph(
id="sunburst",
figure=px.sunburst(df, path=path, values="total_bill"),
)
]
),
html.Div(
[
dash_table.DataTable(
id="table",
columns=[{"name": i, "id": i} for i in df.columns],
data=df.to_dict("records"),
sort_action="native",
)
]
),
]
)
@app.callback(
[
Output("table", "data"),
Output("table", "style_data_conditional"),
Output("title", "children"),
],
[Input("sunburst", "clickData"), Input("sunburst", "hoverData")],
)
def update_table(clickData, hoverData):
click_path = "ALL"
root = False
data = df.to_dict("records")
ctx = dash.callback_context
input_id = ctx.triggered[0]["prop_id"]
style_data_conditional = []
if hoverData:
hover_path = hoverData["points"][0]["id"].split("/")
if len(hover_path) == 1:
selected = [hover_path[0], "none", "none"]
elif len(hover_path) == 2:
selected = [hover_path[0], hover_path[1], "none"]
else:
selected = hover_path
style_data_conditional = [
{
"if": {
"filter_query": "{{day}} = {}".format(selected[0]),
"column_id": "day",
},
"backgroundColor": "#ffe0de",
"color": "white",
},
{
"if": {
"filter_query": "{{time}} = {}".format(selected[1]),
"column_id": "time",
},
"backgroundColor": "#e0deff",
"color": "white",
},
{
"if": {
"filter_query": "{{sex}} = {}".format(selected[2]),
"column_id": "sex",
},
"backgroundColor": "#deffe0",
},
]
if input_id == "sunburst.clickData":
style_data_conditional = []
click_path = clickData["points"][0]["id"].split("/")
selected = dict(zip(path, click_path))
if "sex" in selected:
dff = df[
(df["day"] == selected["day"])
& (df["time"] == selected["time"])
& (df["sex"] == selected["sex"])
]
elif "time" in selected:
dff = df[(df["day"] == selected["day"]) & (df["time"] == selected["time"])]
else:
dff = df[(df["day"] == selected["day"])]
root = True
data = dff.to_dict("records")
# Show all data when returning to the root from an outer leaf
percentEntry = (clickData["points"][0]).get("percentEntry")
if root and percentEntry == 1:
data = df.to_dict("records")
click_path = "ALL"
title = f"Selected From Sunburst Chart: {' '.join(click_path)}"
return data, style_data_conditional, title
if __name__ == "__main__":
app.run_server(debug=True)
Thank you very much, this is a very nice example. I wish you a great day.
Regarding your solution. Can any property of the DataTable be updated in this way? I have looked into the DataTable reference (https://dash.plotly.com/datatable/reference) and DataTables can have so many different properties. I would like to update the property âderived_virtual_row_idsâ in a comparable way as the property âstyle_data_conditionalâ is updated. The logic inside my callback seems to work fine, but no changes to the DataTable are made. (The goal is again to avoid reloading the whole DT and thereby save time)
Thank you
Here in the second example (https://dashr.plotly.com/datatable/interactivity) the property âderived_virtual_row_idsâ is used as an input. In my use case it would be the output and the input is the value of an dccRadioItem.
Yes, all of the properties can be updated in the callback, but some are read-only. In the documentation thatâs noted in some cases, like with âdata_previousâ.
âderived_virtual_row_idsâ indicates the order in which the rows appear after sorting and filtering. It doesnât actually do the sort or the filter if you update this property in a callback.
Dash does support server side sorting and filtering, like in this example: https://dash.plotly.com/datatable/filtering If you have a large data set, using a âcustomâ sort_action or filter_action can reduce the amount of data sent over the network.
Thank you, you helped me again. My final solution is to use the property âfilter_queryâ to filter the DT on the front end based on a column that is hidden from view.
