python 中 time 有三种格式:
float,
struct tuple(time.struct_time 或 datetime.datetime),
str
常用的:
float --> struct tuple: time.localtime( float )
struct time tuple --> str: time.strftime(format, struct time tuple)
str --> struct time tuple: time.strptime(str, format)
struct time tuple --> float : time.mktime(struct time tuple)
struct time tuple --> datetime: datetime(*time_tuple[0:6])
float --> datetime: datetime.datetime.fromtimestamp( float )
datetime --> str: datetime.strftime(format, datetime)
str --> datetime: datetime.strptime(str, format)
datetime --> struct time tuple: datetime.timetuple()
Note:
time 是 float 为基础,小数点后是毫秒,整数部分是秒。(Java 是毫秒,所以,python_time*1000 == Java_time)
datetime 是int, 略去了毫秒部分。datetime tuple 少于 struct_time
1. 当前时间
>>> import time >>> time.time() 1450681042.751>>> time.localtime(time.time()) time.struct_time(tm_year=2015, tm_mon=12, tm_mday=21, tm_hour=15, tm_min=0, tm_sec=2, tm_wday=0, tm_yday=355, tm_isdst=0)>>> time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time())) '2015-12-21 15:01:28'>>> from datetime import datetime >>> datetime.now() datetime.datetime(2015, 12, 21, 14, 58, 38, 279000)>>> datetime.today() datetime.datetime(2015, 12, 21, 14, 59, 20, 204000)>>> now = datetime.now() >>> now.year, now.month, now.day, now.hour, now.minute, now.second, now.microsecond>>> now.isocalendar() # 2015年 第52周 星期一 (2015, 52, 1)>>> now.isoweekday() # 星期几,1:Monday; 而 now.weekday() 返回值从0开始 1
2. 日期字符串--> 日期
>>> s='2015-12-21 15:01:28' >>> timeTuple = datetime.strptime(s, '%Y-%m-%d %H:%M:%S') datetime.datetime(2015, 12, 21, 15, 1, 28)>>> datetime.datetime.strftime('%Y/%m/%d %H:%M:%S', timeTuple)
>>> s='2015-12-21 15:01:28' >>> timeTuple = datetime.strptime(s, '%Y-%m-%d %H:%M:%S') time.struct_time(tm_year=2015, tm_mon=12, tm_mday=21, tm_hour=15, tm_min=1, tm_sec=28, tm_wday=0, tm_yday=355, tm_isdst=-1) >>> time.strftime('%Y/%m/%d %H:%M:%S',timeTuple)
python中时间日期格式化符号:%y 两位数的年份表示(00-99)%Y 四位数的年份表示(000-9999)%m 月份(01-12)%d 月内中的一天(0-31)%H 24小时制小时数(0-23)%I 12小时制小时数(01-12) %M 分钟数(00=59)%S 秒(00-59)%a 本地简化星期名称%A 本地完整星期名称%b 本地简化的月份名称%B 本地完整的月份名称%c 本地相应的日期表示和时间表示%j 年内的一天(001-366)%p 本地A.M.或P.M.的等价符%U 一年中的星期数(00-53)星期天为星期的开始%w 星期(0-6),星期天为星期的开始%W 一年中的星期数(00-53)星期一为星期的开始%x 本地相应的日期表示%X 本地相应的时间表示%Z 当前时区的名称%% %号本身
3. 时间戳
>>> time.mktime(time.strptime(s,'%Y-%m-%d %H:%M:%S')) 1450681288.0>>> int(time.time())
# timestamp to time tuple in UTC timestamp = 1226527167.595983 time_tuple = time.gmtime(timestamp) print repr(time_tuple)
# timestamp to time tuple in local time timestamp = 1226527167.595983 time_tuple = time.localtime(timestamp) print repr(time_tuple)
2. 日期相加减
import datetimenow = datetime.datetime.now() # datetime.datetime(2015, 12, 16, 15, 6, 37, 420000) dayOfweek = datetime.datetime.isoweekday() if dayOfweek == 1: # Mondaylast_time = now + datetime.timedelta(days=-3) else:last_time = now + datetime.timedelta(days=-1)