Description
I am working in a Jupyter notebook and when accessing the selectedpoints attribute of a go.Histogram or the points list in the on_selection callback, the list does not contain integer indices of the selected points but instead just a list of objects.
import plotly.graph_objects as go
import numpy as np
np.random.seed(1)
x = np.random.randn(500)
def on_selection_print(obj, points, selector):
print(points.point_inds)
figure_widget = go.FigureWidget(data=[go.Histogram(x=x)])
figure_widget.update_layout(dragmode="select")
figure_widget.data[0].on_selection(on_selection_print)
figure_widgetWhen selecting points in the histogram, the output looks something like:
[<object object at 0x7ff062c497f0>, <object object at 0x7ff062c497f0>, <object object at 0x7ff062c497f0>, <object object at 0x7ff062c497f0>, <object object at 0x7ff062c497f0>, <object object at 0x7ff062c497f0>]
A call to figure_widget.data[0].selectedpoints returns the same list.
The expected output would be something like:
[0, 12, 13, 26, 31, ..., 2534]
As you can see, all objects are identical (memory address 0x7ff062c497f0) and the objects in the list do not have any attributes. The length of the list corresponds to the number of bars selected if that helps.
I am working with plotly version 4.9.0, ipywidgets version 7.5.1 and notebook version 6.0.1.
UPDATE:
I checked how Plotly.js handles selection for histograms and found that it creates an object for each selected bar, which in turn contains all the points for that bar.
e.g.
{
points: [
0: {..., pointIndices: [1,2,3,4], ...},
1: {..., pointIndices: [5,6,7,8,9], ...},
...
],
range: [...]
}Codepen can be found here: https://codepen.io/meffmadd/pen/zYqGmaw
So the problem seems to be that the points are not correctly serialised for histograms. Without understanding the whole codebase I think there seem to be two options:
- Update the setter to
_js2py_pointsCallbackwhen the figure is a histogram in - Updating the model for the histogram on the Python side to reflect the behaviour of the JavaScript implementation. I don't know how exactly this would work yet.
Any pointers in the right direction are highly appreciated!