import time 
import sys 
reload(sys) 
 
def get_day_of_day(UTC=False, days=0, hours=0, miutes=0, seconds=0): 
 ''''''' 
 if days>=0,date is larger than today 
 if days<0,date is less than today 
 date format = "YYYY-MM-DD" 
 ''' 
 now = time.time() 
 timeNew = now + days*24*60*60 + hours*60*60 + miutes*60 + seconds 
 if UTC : 
 timeNew = timeNew + time.timezone 
 t = time.localtime(timeNew) 
 return time.strftime('%Y-%m-%d %H:%M:%S', t) 
 
#使用UTC时间 两小时前 
t = get_day_of_day(True,0,-2) 
print t 
#当地时间 三天前 
t = get_day_of_day(False,-3) 
print t 
#当地时间 三天后 
t = get_day_of_day(False,3) 
print t

2016-04-30 20:25:56 
2016-05-06 20:25:56