Replacing all cells that are before a certain year in pandas

Question

I have a data set where any date before 2001 is invalid. I want to replace every instance where the date is before 2001 with NaT.

I tried doing something like this, but it would only be for one column and it just isn't correct...

if df['Delivery Date'].dt.year == 2001:
     df['Delivery Date'] = np.nan

`df['Delivery Date']=np.where(df['Delivery Date'].dt.year<2001,np.nan,df['Delivery Date'])` — BENY, May 01 '19 at 19:49
Thanks! I want to do this for the entire data frame. What would be the code for that? — mk2080, May 01 '19 at 19:50

score 0 · Answer 1 · answered May 01 '19 at 19:49

0

df[df['Delivery Date'].dt.year == 2001]['Delivery Date']=np.nan

answered May 01 '19 at 19:49

alexprice

score 0 · Accepted Answer · answered May 01 '19 at 19:51

0

df.loc[df['Delivery Date'].dt.year <= 2001, 'Delivery Date'] = np.nan

Check out this longer post about .loc

answered May 01 '19 at 19:51

Cilantro Ditrek

2 Answers2