Reset selected_rows on call back

Dash Python
1

Hello,

I have created a callback so that when I click on a marker on a map, two tables are created and when I select a row on the first table, the second is updated.

My code is certainly sub-optimal but it nearly works:


@app.callback([Output(component_id='table-index', component_property='data'), 
				Output(component_id='table-index', component_property='columns')],
				[Output('table-company', 'data'), Output('table-company', 'columns')],
				[Input('map-flags', 'selectedData')], [Input('table-index', 'selected_rows')])
def display_selected_data(selectedData, selected_rows):
	global df
	if selectedData:
		index = selectedData['points'][0]['pointIndex']
		country = df.iloc[index]['abbreviation']
	else:
		country = 'us'
	df2 = df.loc[df['abbreviation'] == country].copy()
	df3 = pd.DataFrame.from_dict(df2['index'].values[0])
	df3['country_iso3'] =  df2['iso3'].iloc[0]
	df3 = df3[['country_iso3', 'id' , 'name']]
	df3 = df3.sort_values(['id', 'name'], ascending = [True, True])
	columns = [{'name': col, 'id': col} for col in df3.columns]
	data = df3.to_dict(orient='records')
	
	print(selected_rows)
	if len(selected_rows)>0:
		index = df3['id'].iloc[selected_rows[0]].split(':')[1]
	else:
		index = df3['id'].iloc[0].split(':')[1]
	symbol_list = ss.get_symbol_list(index=index)
	df_inx = pd.DataFrame.from_dict(symbol_list)
	df_inx.drop(['shortName', 'market'], axis=1, inplace=True)
	df_inx = df_inx.sort_values(['longName', 'symbol'], ascending = [True, True])
	columns2 = [{'name': col, 'id': col} for col in df_inx.columns]
	data2 = df_inx.to_dict(orient='records')
	
	return data, columns, data2, columns2

The problem is that I could not find a way to reset the selected_rows argument and, whatever I do, it always remembers the previous value. When this value is out of range, the callback crashes.

I have also tried splitting this into two callbacks. The problem in that case is how to automatically update the second table. In addition, as one row is often pre-selected it is not possible to re-select it.

I am sure there is a better way to accomplish this but I am just starting with Dash.

Best,

Ed

2

This ugly workaround prevents the app from crashing:

if selected_rows[0] > len(df3)-1:
	selected_rows = [0]