time,datetime

time模块：

import time

ces = time.time()      #时间戳 是秒 从 1970.1.1 0.0.0 一直到现在的一个秒
# print(ces)
# time.sleep(1)
# print('haha...')
ces1 = time.ctime()
print(ces1)                       # Tue Dec 19 15:31:49 2017
ces2 = time.localtime()
print(ces2)        # time.struct_time(tm_year=2017, tm_mon=12, tm_mday=19, tm_hour=15,
                    #  tm_min=32, tm_sec=59, tm_wday=1, tm_yday=353, tm_isdst=0)
print(ces2.tm_year)        # 2017
print(time.strftime('%Y-%m-%d %H:%M:%S',ces2))  #   将ces2格式化为 2017-12-19 15:36:21
print(time.gmtime())       #等于 localtime

print(time.strptime('2011-11-11 11:11:11', '%Y-%m-%d %H:%M:%S')) #功能与strftime相反

datetime:

import datetime
ces = datetime.datetime.now()     #获取当前系统时间：
print(ces)                                    #2017-12-19 16:09:27.312303
ces_geshi = ces.strftime('%Y-%m-%d %H:%M:%S')     #将系统时间格式为：
print(ces_geshi)                                             #2017-12-19 16:09:27
ces_tuple=ces.timetuple()          #将系统时间转为元祖：
print(ces_tuple)   #time.struct_time(tm_year=2017, tm_mon=12, tm_mday=19, tm_hour=16, tm_min=9, tm_sec=27,
                                                                #  tm_wday=1, tm_yday=353, tm_isdst=-1)
ces2 = time.mktime(ces_tuple)      #将元祖转为 时间戳：
print(ces2)                               #1513670967.0
ces3 = datetime.datetime.fromtimestamp(ces2)
print(ces3)            # 将时间戳转为 2017-12-19 16:09:27
print(datetime.datetime.fromtimestamp(time.time()))         #time.time()时间戳 2017-12-19 16:09:27.312304

ces1 = datetime.datetime(2011, 11, 11, 11, 11, 11)  # 格式化
print(ces1)  # 2011-11-11 11:11:11

print(datetime.date.today())   #今天的日期 2017-12-19
print(datetime.date.today()+datetime.timedelta(days=2))  #印后天日期2017-12-21
print(datetime.date.today()-datetime.timedelta(days=2))  #印前天日期2017-12-17