Seaborn Barplot和X轴上的格式化日期

Question

I am currently working on visualizing datasets with Seaborn and Pandas. I have some time-dependent data that I would like to graph in bar charts.

However, I am battling with two issues in Seaborn:

1. Formatting dates on the x-axis
2. Only showing a handful of dates (as it doesn't make sense to have every day labeled on a 6 month graph)

I have found a solution for my issues in normal Matplotlib, which is:

import pandas as pd
import seaborn as sns
import matplotlib.pyplot as plt
import matplotlib.dates as mdates

dates = pandas.date_range('1/1/2014', periods=20, freq='m')
df = pandas.DataFrame(
    data={'dt':dates, 'val':numpy.random.randn(N)}
)

fig, ax = plt.subplots(figsize=(10, 6))
ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m'))
ax.bar(df['dt'], df['val'], width=25, align='center')

However, I already have most of my graphs done in Seaborn, and I would like to stay consistent. Once I convert the previous code into Seaborn, I lose the ability to format the dates:

import pandas as pd
import seaborn as sns
import matplotlib.pyplot as plt
import matplotlib.dates as mdates

dates = pandas.date_range('1/1/2014', periods=20, freq='m')
df = pandas.DataFrame(
    data={'dt':dates, 'val':numpy.random.randn(N)}
)

fig, ax = plt.subplots(1,1)
ax.xaxis.set_major_formatter(mdates.DateFormatter('%y-%m'))
sns.barplot(x='dt', y='val', data=df)
fig.autofmt_xdate()

When I run the code, the date format remains unchanged and I can't locate any dates with DateLocator.

Is there any way for me to format my X-Axis for dates in Seaborn in a way similar to Matplotlib with DateLocator and DateFormatter?

Thanks in advance.

Answer 1

No, you cannot use seaborn.barplot in conjunction with matplotlib.dates ticking. The reason is that the ticks for seaborn barplots are at integer positions (0,1,..., N-1). So they cannot be interpreted as dates.

You have two options:

1. Use seaborn, and loop through the labels and set them to anything you want
2. Not use seaborn and have the advantages (and disadvantages) of matplotlib.dates tickers available.