Consider the following data
d = {'color' : pd.Series(['white', 'blue', 'orange']),
'second_color': pd.Series(['white', 'black', 'blue']),
'value' : pd.Series([1., 2., 3.])}
df = pd.DataFrame(d)
Now suppose I want to replace 'white' in columns color and second_color with NaN , in place. I know that one way to do this is
df = df.replace('white', np.NaN)
color second_color value
0 NaN NaN 1.0
1 blue black 2.0
2 orange blue 3.0
But why is it that when I try
df[['color', 'second_color']].replace('white', np.NaN, inplace=True)
instead I don't get the desired results? That is, 'white' doesn't get replaced in df.
