plotly 6.1.2 not showing datetime for FigureWidget

[mgmarino]

The FigureWidget seems to be broken in plotly 6.0 when showing datetime types.

Reproduced using the example here

import plotly.graph_objects as go

import pandas as pd
df = pd.read_csv('https://raw.githubusercontent.com/plotly/datasets/master/finance-charts-apple.csv').assign(Date=lambda x: pd.to_datetime(x.Date))

fig = go.Figure([go.Scatter(x=df['Date'], y=df['AAPL.High'])])
fig.show()

displays correctly with datetime:

With FigureWidget:

import plotly.graph_objects as go

import pandas as pd
df = pd.read_csv('https://raw.githubusercontent.com/plotly/datasets/master/finance-charts-apple.csv').assign(Date=lambda x: pd.to_datetime(x.Date))

fig = go.FigureWidget([go.Scatter(x=df['Date'], y=df['AAPL.High'])])
fig.show()

shows the nanosecond ints:

This was run in VSCode (1.100.2) and also jupyterlab/server (lab == 4.4.3, jupyter-server == 2.16.0)

Seems similar to #5101.

[miohtama]

As a workaround you can do .index.to_pydatetime().tolist():

    index = df.index.to_pydatetime().tolist()

    # Price chart (top subplot)
    fig.add_trace({
        "x": index,
        "y": df["mark_price"],

[miohtama]

I debugged difference of Trace object in Plotly 5.x and 6.x. Apparently DateTimeIndex does not get converted from np.datetime64 to Python datetime.datetime.

Plotly 6.x:

ipdb> pprint(trace)
Scatter({
    'fillcolor': '#aaa',
    'fillpattern': {'shape': '-', 'size': 5, 'solidity': 0.8},
    'hovertemplate': 'asset=USDC<br>timestamp=%{x}<br>% of portfolio=%{y}<extra></extra>',
    'legendgroup': 'USDC',
    'line': {'color': '#FD3216', 'width': 0},
    'marker': {'symbol': 'circle'},
    'mode': 'lines',
    'name': 'USDC',
    'orientation': 'v',
    'showlegend': True,
    'stackgroup': '1',
    'x': array(['2021-06-01T00:00:00.000000000', '2021-06-02T00:00:00.000000000',
                '2021-06-03T00:00:00.000000000', '2021-06-04T00:00:00.000000000',
                '2021-06-05T00:00:00.000000000', '2021-06-06T00:00:00.000000000',
                '2021-06-07T00:00:00.000000000', '2021-06-08T00:00:00.000000000',

Plotly 5.x:

ipdb> pprint(trace)
Scatter({
    'fillcolor': '#aaa',
    'fillpattern': {'shape': '-', 'size': 5, 'solidity': 0.8},
    'hovertemplate': 'asset=USDC<br>timestamp=%{x}<br>% of portfolio=%{y}<extra></extra>',
    'legendgroup': 'USDC',
    'line': {'color': '#FD3216', 'width': 0},
    'marker': {'symbol': 'circle'},
    'mode': 'lines',
    'name': 'USDC',
    'orientation': 'v',
    'showlegend': True,
    'stackgroup': '1',
    'x': array([datetime.datetime(2021, 6, 1, 0, 0),
                datetime.datetime(2021, 6, 2, 0, 0),
                datetime.datetime(2021, 6, 3, 0, 0),
                datetime.datetime(2021, 6, 4, 0, 0),
                datetime.datetime(2021, 6, 5, 0, 0),
                datetime.datetime(2021, 6, 6, 0, 0),

[miohtama]

Here is a monkey-patch to fix the issue:

"""Monkey-patch Plotly 6.x bug: FigureWidget showing nanoseconds instead of dates.

- Workaround bug https://github.com/plotly/plotly.py/issues/5210
"""

from importlib.metadata import version, PackageNotFoundError
import datetime

from packaging.version import Version


try:
    pkg_version = version("plotly")
except PackageNotFoundError:
    pkg_version = None


if (pkg_version is not None) and Version(pkg_version) <= Version("6.1.2"):

    import numpy
    import pandas
    from plotly.graph_objs import Figure

    def fix_trace_x_axis_dates(self: Figure):
        for trace in self.data:
            item = trace.x[0]
            # Detect datetime64 and convert it to native Python datetime that show() can handle
            if isinstance(trace.x, numpy.ndarray):
                if isinstance(item, numpy.datetime64):
                    trace.x = pandas.Series(trace.x).dt.to_pydatetime().tolist()


    # Run in the monkey patch,
    # so that traces are fixed when fig.show() is called
    _old_show = Figure.show
    def _new_show(self: Figure, *args, **kwargs):
        fix_trace_x_axis_dates(self)
        _old_show(self, *args, **kwargs)
    Figure.show = _new_show