[BUG] numpy array not correctly read back from figure data
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 24.4k
- Forks
- 2.3k
- Avg merge
- 2d 7h
- Merged PRs (30d)
- 13
Description
Please provide us your environment, so we can easily reproduce the issue:
Windows 10, python 3.12
dash 3.0.4
dash-core-components 2.0.0
dash-html-components 2.0.0
plotly 6.1.1
numpy 2.2.5
Describe the bug
When I create a go.Figure and add a trace with x and/or y being numpy arrays, the plot is created correctly.
However, when I want to read back the data, some representation of the numpy array is provided as dictionary: {‘dtype’: ‘f8’, ‘bdata’: ‘AAAAAAAA8D8AAAAAAAAAQAAAAAAAAAhAAAAAAAAAEEAAAAAAAAAUQA==’, ‘_inputArray’: {‘0’: 1, ‘1’: 2, ‘2’: 3, ‘3’: 4, ‘4’: 5, ‘bdata’: ‘AAAAAAAA8D8AAAAAAAAAQAAAAAAAAAhAAAAAAAAAEEAAAAAAAAAUQA==’, ‘dtype’: ‘f8’, ‘shape’: ‘5’}}
As also described in https://community.plotly.com/t/changed-behaviour-in-dash-2-18-2-using-numpy-1-26-4-when-reading-figure-into-callback-on-linux/90614
import dash
from dash import dcc, html, Input, Output, State
import plotly.graph_objs as go
import numpy as np
# Initialize the Dash app
app = dash.Dash(__name__)
# Create some sample data using numpy
x_data = np.array([1.0, 2.0, 3.0, 4.0, 5.0])
y_data = np.array([2.0, 1.5, 3.5, 2.0, 5.0])
# Define the layout of the app
app.layout = html.Div([
dcc.Graph(id='scatter-plot'),
html.Button('Generate Plot', id='generate-button', n_clicks=0),
html.Button('Print Data', id='print-button', n_clicks=0)
])
# Callback to generate the ScatterGL plot
@app.callback(
Output('scatter-plot', 'figure'),
Input('generate-button', 'n_clicks')
)
def update_figure(n_clicks):
# Create a ScatterGL trace
trace = go.Scattergl(
x=x_data,
y=y_data,
mode='markers',
marker=dict(size=10, color='blue')
)
# Create the figure
fig = go.Figure(data=[trace])
fig.update_layout(title='ScatterGL Plot', xaxis_title='X Axis', yaxis_title='Y Axis')
return fig
# Callback to print the x and y data from the figure
@app.callback(
Output('print-button', 'children'),
Input('print-button', 'n_clicks'),
State('scatter-plot', 'figure')
)
def print_data(n_clicks, figure):
if n_clicks > 0 and figure is not None:
# Extract the x and y data from the figure
x_values = figure['data'][0]['x']
y_values = figure['data'][0]['y']
# Print the x and y values
print("X values:", x_values)
print("Y values:", y_values)
return "Print Data"
# Run the app
if __name__ == '__main__':
app.run_server(debug=True)
Expected behavior
A) Throw an Exception when numpy arrays are not supported
B) If numpy arrays are supported return the numpy array or the numpy array converted to a valid list
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by running the provided Dash reproduction with Python 3.12, numpy 2.2.5, plotly 6.1.1, and the listed Dash versions, then inspect the figure data returned through the callback State. Compare the x and y values with the original arrays; done means unsupported arrays raise an exception or are returned as numpy arrays or valid lists.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- numpy, plotly, python
- Domain
- data-visualization
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100