NaN¶

fillna for selected columns within groups¶

df['col'] = df.groupby('grp')['col'].ffill()

df.groupby¶

df.groupby mean does not support "skipna=False"

drop nan from array¶

arr[~pd.isnull(arr)]

check df nan values¶

sns.heatmap(df.isnull(), yticklabels=False, cbar=False, cmap='viridis')