from dateutil.relativedelta import relativedelta
from datetime import datetime
s = '明天'
if s.find('明天') > -1:
    now = datetime.now()
    print(now)
    print(now + relativedelta(days=1))
    print((now + relativedelta(days = 1)).strftime('%Y-%m-%d %H:%M:%S'))
2018-08-04 16:59:15.890940
2018-08-05 16:59:15.890940
2018-08-05 16:59:15
from dateutil.relativedelta import relativedelta
from datetime import datetime
ss = '下个月7号飞东南亚泰国普吉岛'
if ss.find('下个月')> -1:
    now = datetime.now()
    print(now)  # day 是指定日期七号,days是在当前的日期上加七天,+加号,-减号
    print(now + relativedelta(months = 1, day =7))
    print((now + relativedelta(months = 1 ,days = 7)).strftime('%Y-%m-%d %H:%M:%S'))
    print((now + relativedelta(months = 1 ,day = 7)).strftime('%Y-%m-%d %H:%M:%S'))
2018-08-04 17:06:12.619705
2018-09-07 17:06:12.619705
2018-09-11 17:06:12
2018-09-07 17:06:12