Find the closest date to a given date

This function will return the datetime in items which is the closest to the date pivot.

def nearest(items, pivot):
    return min(items, key=lambda x: abs(x - pivot))

The good part this function works on types other than datetime too out of the box, if the type supports comparison, subtraction and abs, e.g.: numbers and vector types.

As answered on this link link, 'truncate' function is there for you.

df.truncate(before='2012-01-07')

Or you can use get_loc with 'nearest', 'backfill' or 'ffill' option.

df.iloc[df.index.get_loc(datetime.datetime(2016,2,2),method='nearest')]