Identify if a record is within 1 year in Pandas

Question

I am trying to identify records that expire within 1 year of today's date. This is the code I have and it doesn't work because I can't add or subtract integers from dates. Can someone assist? I know this is simple.

from datetime import date

today = date.today()

mask = (df['[PCW]Contract (Expiration Date)'] <= today + 365)

Can you add some of the dataframe to the question? – Oddaspa Oct 23 '20 at 20:04 — Oddaspa, Oct 23 '20 at 20:04
There are years with 366 days. Does that matter? – Bill Huang Oct 23 '20 at 20:08 — Bill Huang, Oct 23 '20 at 20:08

Oddaspa · Accepted Answer · 2020-10-23T20:45:57.857

1

You need to use time deltas.

from datetime import timedelta
one_year = timedelta(days=365)
mask = (df['[PCW]Contract (Expiration Date)'] <= today + one_year)

Assuming you are using datetime objects in your dataframe.

UPDATE

import pandas as pd
import numpy as np
df = pd.DataFrame({'[PCW]Contract (Expiration Date)' :["2020-01-21T02:37:21", '2021-01-21T02:37:21', '2022-01-21T02:37:21']})
s = pd.to_datetime(df['[PCW]Contract (Expiration Date)'])
one_year = np.timedelta64(365,'D')
today = np.datetime64('today')
mask = s <= today + one_year
mask

Output

0     True
1     True
2    False
Name: [PCW]Contract (Expiration Date), dtype: bool

edited Oct 23 '20 at 20:45

answered Oct 23 '20 at 20:07

Oddaspa

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I get this error: Invalid comparison between dtype=datetime64[ns] and date – Alex Dowd Oct 23 '20 at 20:11
You can also use [`pd.Timdelta(days=365)`](https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.Timedelta.html). – Ch3steR Oct 23 '20 at 20:11
@Ch3steR I get the same error – Alex Dowd Oct 23 '20 at 20:12
I assume that the type of df['[PCW]...'] is numpy.datetime64. Then you should use one_year = numpy.timedelta64(365,'D') – Oddaspa Oct 23 '20 at 20:16
@Oddaspa sorry this will probably help. the dates came as strings, i formatted them to datetime with pd.to_datetime. – Alex Dowd Oct 23 '20 at 20:22
I updated the answer to contain an example. – Oddaspa Oct 23 '20 at 20:46

Identify if a record is within 1 year in Pandas

1 Answers1

UPDATE