I have a DataFrame indexed by date. I would like to be able to Null out all rows where the index is greater than some value (like today) but keep them in the DataFrame. What's the best way to do this? For instance this
10/20/16 15, 20 10/25/16 13, 12 10/30/16 16, 15
--> 10/30/16 should go to NaN, NaN