How to extract the last year (YYYY) from a YYYY-YY format column in Pandas

April 15, 2022

I am trying to extract the last year (YY) of a fiscal date string in the format of YYYY-YY. e.g The last year of this ‘1999-00’ would be 2000.

Current code seems to cover most cases other than this.

import pandas as pd
import numpy as np


test_df = pd.DataFrame(data={'Season':['1996-97', '1997-98', '1998-99', 
'1999-00', '2000-01', '2001-02',
'2002-03','2003-04','2004-05', 
'2005-06','2006-07','2007-08', 
'2008-09', '2009-10', '2010-11', '2011-12'],
'Height':np.random.randint(20, size=16), 
'Weight':np.random.randint(40, size=16)})

I need a logic to include a case where if it is the end of the century then my apply method should add to the first two digits, I believe this is the only case I am missing.

Current code is as follows:

test_df['Season'] = test_df['Season'].apply(lambda x: x[0:2] + x[5:7])

>Solution :

Here you go! Use the following function instead of the lambda:

def get_season(string):
    century = int(string[:2])
    preyear = int(string[2:4])
    postyear = int(string[5:7])
    if postyear < preyear:
        century += 1
    # zfill is so that "1" becomes "01"
    return str(century).zfill(2) + str(postyear).zfill(2)