ENH/CLN: add BoxPlot class inheriting MPLPlot

[sinhrks]

Like #7809, added DataFrame.plot(kind='box') to plot boxplot under the common plotting method.

NOTE: DataFrame.boxplot remains untouched (few lines are modified to share some definitions).
NOTE: This is based on #7736.

import pandas as pd
import numpy as np
pd.options.display.mpl_style = 'default'
df = pd.DataFrame(np.random.randn(100, 5))
ax = df.plot(kind='box')

One enhancement is easier colorization by passing color keyword. You can pass dict with keys are boxes, whiskers, medians and caps. If some keys are missing in the dict, default colors are used for the corresponding artists. Also, boxplot has sym keyword to specify fliers style (This is mpl keyword and simply forward to mpl).

color = dict(boxes='DarkGreen', whiskers='DarkOrange',
             medians='DarkBlue', caps='Gray')
ax = df.plot(kind='box', color=color)

[jreback]

hmm, any way to get rid of DataFrame.boxplot and replace with this? (I think you did that with hist yes?)

[sinhrks]

DataFrame.boxplot and hist still remain. This is because DataFrame.plot doesn't cover GroupBy cases yet.

My idea to replace boxplot is enhance DataFrame.plot to support GroupBy in consistent way. Then, plotting.scatter, DataFrame.hist and DataFrame.boxplot can be deprecated (hopefully by 0.15).

[jreback]

@TomAugspurger can you have a look

[TomAugspurger]

Update this line for all the extras you've added recently.

[sinhrks]

The docstring is being modified in #8037 to exclude specific kinds. Thus it is OK to leave it.

[TomAugspurger]

@sinhrks want to rebase now that I merged #7736

Or actually you may not need to since they're separate commits. I'll look.

[jorisvandenbossche]

@jreback Do we really want to get rid of DataFrame.boxplot() et al? Because this is really used a lot .. But, for this PR a bit a seperate discussion, as the questions doesn't hinder to improve the .plot(kind='box')

[jreback]

@jorisvandenbossche I don't think this touches DataFrame.boxplot(); it should really just (not sure if this PR does it), make it an alias for df.plot(kind='box') that's it really.

I think @sinhrks changes df.plot(kind='hist') to do basically the same thing (but not touch the API)

[jorisvandenbossche]

Like this, it seems like the ability to plot boxplots, is only added in 0.15, which is of course not the case. So I would start with already mentioning both ways here, and then say that the plot(kind='box') way is only added in 0.15?

[jorisvandenbossche]

@jreback yes, but I interpreted your "get rid of DataFrame.boxplot" as deprecating it in the API, not as just making this an alias for plt(kind='box')

@sinhrks What are, as for now with this PR, still the differences between df.boxplot() and df.plot(kind='box')? (because looking at the code, df.boxplot() is not yet simply a call to df.plot(kind='box'))

[sinhrks]

Unable to replace existing boxplot now, reason is described above.

I think there are some options to "get rid of" boxplot. Making alias or completely remove after some span... It should be discussed separately including hist and scatter also.

[TomAugspurger]

Extra . at the end of the line.

[sinhrks]

Thanks, fixed.

[TomAugspurger]

OK, thanks @sinhrks.

[TomAugspurger]

FYI, build failed: https://travis-ci.org/pydata/pandas/builds/33461054

Looking into it. Doesn't seem related to this one.