Add axes.violinplot test from test_datetime.py #27521
Conversation
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From #27485 (comment):
While I agree that the "primary" piece of violinplot generally doesn't make sense/doesn't work with dates, there is still a piece that should work (Though I admittedly haven't tested it) |
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@ksunden Not sure which "piece" you are talking about... Should I test again with import matplotlib.pyplot as plt
import numpy as np
from datetime import datetime, timedelta
from collections import defaultdict
import pytest
import matplotlib as mpl
@pytest.mark.xfail(reason="Test for violinplot not written yet")
@mpl.style.context("default")
class TestViolinPlot:
def test_violinplot(self):
np.random.seed(42)
n_samples = 100
dates_values = [(datetime(2023, 1, 1) + timedelta(days=np.random.randint(1, 15)), np.random.randn())
for _ in range(n_samples)]
values_by_date = defaultdict(list)
for date, value in dates_values:
values_by_date[date.toordinal()].append(value)
date_ordinals, values = zip(*values_by_date.items())
date_timedeltas = [datetime.fromordinal(date) - datetime(2023, 1, 1) for date in date_ordinals]
fig, ax = plt.subplots()
result = ax.violinplot(values, positions=date_timedeltas, widths=timedelta(days=5), showmeans=True, showextrema=True)
ax.set_title('Violin Plot with DateTime and Timedelta Positions')
ax.set_xticks(date_timedeltas)
ax.set_xticklabels([datetime.fromordinal(date).strftime('%Y-%m-%d')
for date in date_ordinals], rotation=45, ha='right')
ax.set_xlabel('Dates')
ax.set_ylabel('Values')
assert result is not None, "Failed to create violin plot"Pytest Output: ================================================= test session starts =================================================
platform win32 -- Python 3.11.5, pytest-7.4.3, pluggy-1.3.0
Matplotlib: 3.8.2
Freetype: 2.6.1
rootdir: C:\Users\XXXX
plugins: anyio-3.5.0, asdf-3.0.1, mpl-0.16.1
collected 1 item
XXXX\test_untitled2.py x [100%]
================================================= 1 xfailed in 0.50s ==================================================Edit: Corrected grammatical mistakes. |
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Oops, I wrote the wrong test in the PR description. (The test gives an output (plus it doesn't deal with timedelta); my bad!) |
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from datetime import datetime, timedelta
import numpy as np
import matplotlib.pyplot as plt
np.random.seed(19680801)
n_samples = 100
values = np.random.randn(n_samples)
fig, ax = plt.subplots()
result = ax.violinplot(values, positions=[datetime(2023, 1, 10)], widths=[timedelta(days=10)], showmeans=True, showextrema=True)Gives:
This shows a plot that is centered on on a datetime and has a width given by the time delta. It automatically sets the ticks and formatter for the X axis. So it is demonstrating that units are adhered to by positions/width. A more complete test would probably have multiple violins (possibly on the same Axes) with different widths/positions/etc. While the values are not handed datetime values (in any sense) here, which is one way violin could have (but does not fully) supported units, the position and width (x-axis) values are supported. |
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@ksunden Could you please review? |
PR summary
This PR is modeled for #26864
Axes.violinplot.Image of generated plot: