import time, datetime
# 字串轉時間
t = time.strptime("2018-12-21 10:22:56", "%Y-%m-%d %H:%M:%S")
#print(t)
#time.struct_time(tm_year=2018, tm_mon=12, tm_mday=21, tm_hour=10, tm_min=22, tm_sec=56, 
# tm_wday=4, tm_yday=355, tm_isdst=-1)
y, m, d, h, min,s = t[0:6]
print(datetime.datetime(y,m,d,h,min,s))
# 2018-12-21 10:22:56
t3 = datetime.datetime(y,m,d,h,min,s)
t4 = datetime.datetime.now()
print(t3-t4)
# datetime.timedelta(123, 48597, 819290)
print(t4>t3)
# False
print((t4-t3).days)
# -124
 

date_time1 = datetime.datetime.strptime("2018-08-21 18:55", "%Y-%m-%d %H:%M")
date_time2 = datetime.datetime.strptime("2018-08-20 12:30", "%Y-%m-%d %H:%M")