Pandas: filling missing values by mean in each group

Question

This should be straightforward, but the closest thing I\'ve found is this post: pandas: Filling missing values within a group, and I still can\'t solve my problem....

<

Answer 1

The featured high ranked answer only works for a pandas Dataframe with only two columns. If you have a more columns case use instead:

df['Crude_Birth_rate'] = df.groupby("continent").Crude_Birth_rate.transform(
    lambda x: x.fillna(x.mean()))