Inconsistent color arguments

[thomas-haslwanter]

In pandas 0.17.0.rc1 there is an inconsistency in the color arguments: once it is "color", other times it is "colors":

df.plot(kind='bar', color= ....)
df.plot(kind='pie', colors= ...)

[jreback]

hmm that seems wrong
want to do a pr to fix?

[thomas-haslwanter]

Since I don't really know the code in pandas, I would prefer not to mess around with it. Also, I have to admit that I have close to zero experience with pr's.
Sorry :(

[sinhrks]

This was intentional to be compat with mpl (#6976).

• http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.bar
• http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.pie

I'm not sure which kwds should be used here.

• Use color to minimize user code change, because other function uses color.
• Use colors because pandas can generally accept multiple colors. MPL seems to use colors when they expect multiple input.

[TomAugspurger]

Don't forget that we also accept c to refer to a column in scatter. It'd be nice to unify these someday.

[sumitbinnani]

@jreback @sinhrks
Is the suggested change suggested desired? I would like to give it a try.

Also, can we have both the parameters and implement using whichever is not None?

[sinhrks]

@sumitbinnani There is an existing logic to handle color and colors. pie, scatter and hexbin should use use the same method also.

https://github.com/pydata/pandas/blob/master/pandas/tools/plotting.py#L925

[sumitbinnani]

• pie, ``scatterand hexbin` call the `init` of MPLPlot which in turn already calls `_validate_color_args`. However, in case of class `PiePlot`, the method `_validate_color_args` have been overridden. So, I guess, the issue might be resolved by removing the overridden method.
• Also, _validate_color_args is overridden in BoxPlot and does not handle colors kwd. So, a deprecation warning might need to be included here.

Kindly correct me if the above changes does not meet the requirements, and something else needs to be taken care of, @sinhrks?

[sinhrks]

Looks OK.

One concern is MPL hexbin can accept color kw separately. It looks no effects, but pls check overwritting color kw in pandas side should not disturb any MPL use case.

http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.hexbin