Why are colors not working in matplotlib for this example?

Question

Why am I not seeing any red colors for the negative values here?

df = pd.DataFrame([1, -2, 3, -4])
df['positive'] = df[[0]]>0
df[[0]].plot(kind='bar', color=df.positive.map({True: 'g', False: 'r'}))

I am expecting negative values to be red!

As per our discussion below, this is a bug in the latest version of pandas 0.20.2.

Answer 1

This is due to the bug as mentioned by @johnchase.

One workaround till it gets resolved :

print(''.join(df.positive.map({True: 'g', False: 'r'}).values))    # 'grgr'
df[[0]].plot(kind='bar', color=''.join(df.positive.map({True: 'g', False: 'r'}).values))

which outputs