DataFrame.plot error when both 'color' and 'style' arguments are passed

[davidbrochart]

In pandas 0.15.2, when passing both arguments 'color' and 'style' to the plot method, there is an error which I think should be raised only when there is a color symbol in the style string. But in the example below, the error is raised even though there is no color symbol in the line string:

from pandas import DataFrame
import numpy as np
df = DataFrame({'a': np.random.rand(10), 'b': np.random.rand(10), 'c': np.random.rand(10)})
df.plot(color = ['red', 'black', 'blue'], style = ['-', '--', '-'])

The error is not clear (TypeError: expected string or buffer). This should be fixed, although it is easy to work around:

df.plot(style = ['r-', 'k--', 'b-'])

[TomAugspurger]

It looks like your example is supposed to work, it's just that our regex in this block checking for the color is expecting a string, not a list of strings. Notice that df.a.plot(color = 'red', style = '-') works correcly.

It should be a pretty quick fix, just check if style is an array-like of strings and check if any of those match the regex. Interested in submitting a PR?

[davidbrochart]

Sure, submitting a PR will be a first time for me, but there is always a first time ;-)

[TomAugspurger]

There is indeed! We're here if you have troubles. The only trick is to correctly determine whether it's a string or list. There's a function in pandas/core/common.py is_list_like. You should be able to use it with com.is_list_like.

[davidbrochart]

It looks like I've submitted a PR ;-)
#9673

[davidbrochart]

I've submitted a new PR #9674 with a test for the bug fix.

[TomAugspurger]

Closed via #9674