文档: http://labix.org/python-dateutil pypi: https://pypi.org/project/python-dateutil/
安装
pip install python-dateutil
代码示例
from datetime import datetime, date
from dateutil.relativedelta import relativedelta
now = datetime.now()
print(now)
print(now - relativedelta(months=3))
"""
2019-01-09 18:13:28.791192
2018-10-09 18:13:28.791192
"""
today = date.today()
print(today)
print(today - relativedelta(months=3))
"""
2019-01-09
2018-10-09
"""
参考: