datetime模块
datetime类的类方法 返回的都是datetime类实例化后的对象
today()返回本地失去的当前时间的datetime对象
In [90]: import datetime In [91]: datetime.datetime.today() Out[91]: datetime.datetime(2020, 9, 25, 17, 29, 12, 94402)
now(tz=None) 放回当前时间datetime对象，时间到微妙，如果tz为None，返回和today()相同
In [3]: datetime.datetime.now() Out[3]: datetime.datetime(2020, 9, 25, 18, 5, 59, 826495)
当使用时区tz的时候会报错
In [6]: datetime.datetime.now(8) --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-6-dd94d7ca2e60> in <module> ----> 1 datetime.datetime.now(8) TypeError: tzinfo argument must be None or of a tzinfo subclass, not type 'int'
使用第三方模块pytz解决
In [2]: pip install pytz Requirement already satisfied: pytz in c:usersasus-pcappdatalocalprogramspythonpython35libsite-packages You are using pip version 9.0.1, however version 20.2.3 is available. You should consider upgrading via the 'python -m pip install --upgrade pip' command. Note: you may need to restart the kernel to use updated packages. In [4]: import pytz In [13]: pytz.timezone(pytz.country_timezones('us')[1]) Out[13]: <DstTzInfo 'America/Detroit' LMT-1 day, 18:28:00 STD> In [14]: us_tz=pytz.timezone(pytz.country_timezones('us')[1]) In [15]: datetime.datetime.now(us_tz) Out[15]: datetime.datetime(2020, 9, 25, 6, 15, 15, 825404, tzinfo=<DstTzInfo 'America/Detroit' EDT-1 day, 20:00:00 DST>) In [16]: datetime.datetime.now() Out[16]: datetime.datetime(2020, 9, 25, 18, 15, 22, 882819)
utcnow() 没有时区的当前时间，比当前时区的慢8个小时
In [17]: datetime.datetime.utcnow() Out[17]: datetime.datetime(2020, 9, 25, 10, 17, 21, 792524)
fromtimestamp(timestamp,tz=None)
In [19]: datetime.datetime.fromtimestamp(1601000625.553865) Out[19]: datetime.datetime(2020, 9, 25, 10, 23, 45, 553865)
datetime对象的方法
构造datetime对象
In [20]: datetime.datetime(2010,1,3,10,29,25) Out[20]: datetime.datetime(2010, 1, 3, 10, 29, 25)
datetime对象的属性（year、month、day、hour、minute、second、microsecond）
In [22]: tm=datetime.datetime(2010,1,3,10,29,25) In [23]: tm.year Out[23]: 2010 In [25]: tm.minute Out[25]: 29
weekday() 返回周的某天，周一为0
In [27]: tm=datetime.datetime(1988,11,26,10,29,25) In [28]: tm.weekday() Out[28]: 5
isoweekday() 返回周的某天
In [29]: tm.isoweekday() Out[29]: 6
date() 返回日期date对象
In [31]: tm.date() Out[31]: datetime.date(1988, 11, 26)
time() 返回时间time对象
In [32]: tm.time() Out[32]: datetime.time(10, 29, 25)
replace() 修改并返回新的时间
In [33]: tm.replace(11) Out[33]: datetime.datetime(11, 11, 26, 10, 29, 25) In [34]: tm.replace(1999,7,1) Out[34]: datetime.datetime(1999, 7, 1, 10, 29, 25)
isocalendar() 返回一个三元组（年，第几周，该周的某一天）
In [35]: tm.isocalendar() Out[35]: (1988, 47, 6)
timestamp()返回到微秒的时间戳（从时间元年到现在）
In [18]: datetime.datetime.utcnow().timestamp() Out[18]: 1601000625.553865
Python日期格式化
类方法strptime(date_string,format) 返回datetime对象
In [38]: time_str=datetime.datetime.strptime('2019/10/11 18:53',"%Y/%m/%d %H:%M") In [39]: time_str Out[39]: datetime.datetime(2019, 10, 11, 18, 53)
对象方法 strftime(format) 返回字符串
In [41]: time_str.strftime('%H:%M:%S %d-%m-%y') Out[41]: '18:53:00 11-10-19'
In [45]: "{0:%H}:{0:%M}:{0:%S} {0:%d}-{0:%m}-{0:%y}".format(time_str) Out[45]: '18:53:00 11-10-19'
timedelta对象
构造方法
datetime.timedelta(days=0,seconds=0,microseconds=0,milliseconds=0,minutes=0,hours=0,weeks=0)
year=datetime.timedelta(days=360)
计算
In [46]: datetime.timedelta(hours=8) Out[46]: datetime.timedelta(0, 28800) In [47]: t_d=datetime.timedelta(hours=8) In [48]: datetime.datetime.now() Out[48]: datetime.datetime(2020, 9, 25, 19, 35, 57, 915668) In [49]: datetime.datetime.now()-t_d Out[49]: datetime.datetime(2020, 9, 25, 11, 36, 5, 375506)
求时间戳
In [52]: datetime.timedelta(hours=8).total_seconds() Out[52]: 28800.0
time标准库
sleep(seconds) 挂起当前进程多少秒
In [55]: time.sleep(2)
localtime() 返回当前时间的struct_time格式
语法：
localtime([seconds]) -> (tm_year,tm_mon,tm_mday,tm_hour,tm_min,tm_sec,tm_wday,tm_yday,tm_isdst)
In [3]: lt=time.localtime() In [4]: lt Out[4]: time.struct_time(tm_year=2021, tm_mon=7, tm_mday=9, tm_hour=3, tm_min=13, tm_sec=57, tm_wday=4, tm_yday=190, tm_isdst=1)
In [17]: type(time.localtime(2))
Out[17]: time.struct_time
gmtime() 返回UTC时间的struct_time格式
语法：
gmtime([seconds]) -> (tm_year, tm_mon, tm_mday, tm_hour, tm_min,tm_sec, tm_wday, tm_yday, tm_isdst)
In [5]: lt2=time.gmtime() In [6]: lt2 Out[6]: time.struct_time(tm_year=2021, tm_mon=7, tm_mday=9, tm_hour=7, tm_min=15, tm_sec=59, tm_wday=4, tm_yday=190, tm_isdst=0)
In [8]: lt2.tm_hour
Out[8]: 7
mktime(tuple) 返回时间元年到指定时间的时间戳
语法：
mktime(tuple) -> floating point number
In [24]: datetime.datetime.utcnow().timestamp(),time.mktime(time.localtime()) Out[24]: (1625830138.296473, 1625815738.0) In [25]: datetime.datetime.utcnow().timestamp(),time.mktime(time.localtime(2)) Out[25]: (1625830363.588682, 2.0)
strftime() 返回时间的字符串格式
语法：
strftime(format[, tuple]) -> string
In [26]: time.strftime("%Y-%m-%d",time.localtime()) Out[26]: '2021-07-09'
strptime(string, format) 转换字符串格式时间为结构化时间
语法：
strptime(string, format) -> struct_time
In [30]: time.strptime("2020-12-10","%Y-%m-%d") Out[30]: time.struct_time(tm_year=2020, tm_mon=12, tm_mday=10, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=345, tm_isdst=-1)