Clear selectedData on FigureChange

Dash Python
1

Dear Dash Community,

I am quite new to Dash but I am very impressed of the possibilities. However, I am facing an issue I cannot get rid of.

I have an application with 2 graphs let’s call the graph A and graph B. I use the selectedData property of B to make a selection of the dataframe of A. Furthermore, there is a slider S to toggle different dataframes. So if the slider changes the figures in A and B are updated. The problem is that when updating the figures of A and B the selectedData property of B is not cleared and thus this might lead to unwanted behaviour. Is it possible to either clear the data on figure change automatically by calling a function something click A.clearSelection().

Best
Daniel

small sketch:

sketch
sketch1241×875 57.1 KB

The two callbacks in an abbreviated form:

@app.callback(
    dash.dependencies.Output('img0', 'figure'),
    [dash.dependencies.Input('slider', 'value'),
     dash.dependencies.Input('scatter', 'selectedData')])
def update_images(sliderVal,selectedData):

and

@app.callback(
    dash.dependencies.Output('scatter', 'figure'),
    [dash.dependencies.Input('slider', 'value'),
     dash.dependencies.Input('img0','selectedData')])
@cache.memoize()
def update_graph(slider,img0_lasso):
2

Let’s denote the graph where you select data master and the other graph slave. Furthermore, add a Store element with id selection_cache. You could then do something like,

@app.callback(Output('master', 'figure'), [Input('slider', 'value')], )
def update_master(data):
    return {}  # update master graph


@app.callback(Output('selection_cache', 'data'), [Input('slider', 'value'), Input('master', 'selectedData')],
              [State('selection_cache', 'data')])
def update_selection(data, selected_data, state):
    # Reset selection when data changes.
    if state is not None and state["md5"] != hashlib.md5(json.dumps(data)):
        selected_data = None
    # Save selected data and md5 hash of the full dataset.
    return {"md5": hashlib.md5(json.dumps(data)), "selected_data": selected_data}


@app.callback(Output('slave', 'figure'), [Input('slider', 'value'), Input('selection_cache', 'data')], )
def update_slave(data, selection_cache):
    selected_data = selection_cache["selected_data"] if selection_cache is not None else None
    return {}  # update slave graph
1 Like