python timedelta() 和relativedelta()的区别

python timedelta() 和relativedelta()的区别

在挖掘特征时，往往需要按照时间段来统计特征，例如最近一个月、最近3个月、最近半年、最近一年 某用户的行为数据，那么如何计算筛选这些时间点呢？下面就来介绍两种方法：

1. timedelta()函数仅支持days和weeks参数

2. 而relativedelta()函数可以支持年 、月、日、周、时、分、秒的参数
   后者的功能更加强大，在实际中用到的较多。

import datetime
from dateutil.relativedelta import relativedelta
now_date = datetime.datetime.now()
print "now_date:", now_date
two_year_bf = now_date - relativedelta(months=24)
print two_year_bf
print now_date + datetime.timedelta(days=2)
print now_date + datetime.timedelta(weeks=1)
print "**************************"
print now_date + relativedelta(years=1)
print now_date + relativedelta(months=1)
print now_date + relativedelta(days=1)
print now_date + relativedelta(weeks=1)
print now_date + relativedelta(hours=1)
print now_date + relativedelta(minutes=1)
print now_date + relativedelta(seconds=1)
--------------------result-------------------
now_date: 2020-01-07 19:36:32.935444
2020-01-08 19:36:32.935444
2020-01-14 19:36:32.935444
******************************
2021-01-07 19:36:32.935444
2020-02-07 19:36:32.935444
2020-01-08 19:36:32.935444
2020-01-14 19:36:32.935444
2020-01-07 20:36:32.935444
2020-01-07 19:37:32.935444
2020-01-07 19:36:33.935444