How to find the .describe() based on a a column duplicate criteria?

Question

For example, my dataframe consists of

Date	ID	Result
1/5/2020	B213	60
1/6/2020	B213	70
1/5/2021	B213	50
1/9/2020	L914	75
1/9/2021	L914	76

and i want to find out every year what is the mean, median, percentiles of the IDs individually. How do i do that? I used .describe() but I realised it is to collate the entire dataframe and it gives me the percentiles and mean median of the entire dataframe but that's not what I need. (sorry for my bad English. English isn't my first language.) I'm using pandas jupyter.

Answer 1

first is it a way to format your dataframe :

df['year']=df['Date'].str[-4:]
df_mean=df.groupby(by=['ID','year']).mean().reset_index().rename(columns={'Result':'mean'})
df_median=df.groupby(by=['ID','year']).median().reset_index().rename(columns={'Result':'median'})
df_mean=df_mean.join(df_median['median'])
df_mean