error message when using datetime to convert a string to datetime object

The code is as follows:

for i in range(0,len(df)):
    df['date'][i] = datetime.strptime(df['date'][i], '%y-%m-%d %H:%M:%S')

I got the error message:

time data ‘2019-12-06 09:00:00’ does not match format ‘%y-%m-%d %H:%M:%S’

I don’t know why it gives me this message and how to handle it?

>Solution :

The issue is %y, which truncates the year by its last two digits. You need %Y instead, which will give you four digits for the year.