day6 time和datetime模块
time模块
time模块提供各种操作时间的函数
#1、时间戳 1970年1月1日之后的秒
#2、元组 包含了：年、日、星期等... time.struct_time
#3、格式化的字符串 2014-11-11 11:11
（1）asctime(p_tuple=None)
def asctime(p_tuple=None): # real signature unknown; restored from __doc__
"""
asctime([tuple]) -> string
Convert a time tuple to a string, e.g. 'Sat Jun 06 16:26:11 1998'.
When the time tuple is not present, current time as returned by localtime()
is used.
"""
return ""
asctime()返回当前系统的时间，如下：
>>> time.asctime()
'Sun May 28 13:32:04 2017'
（2）clock()
def clock(): # real signature unknown; restored from __doc__
"""
clock() -> floating point number
Return the CPU time or real time since the start of the process or since
the first call to clock(). This has as much precision as the system
records.
"""
return 0.0
clock()返回CPU系统当前的时间，或者真实时间，从开始到第一次使用clock()。
>>> time.clock()
0.44741
（3）clock_getres(clk_id)
def clock_getres(clk_id): # real signature unknown; restored from __doc__
"""
clock_getres(clk_id) -> floating point number
Return the resolution (precision) of the specified clock clk_id.
"""
return 0.0
（4）clock_gettime(clk_id)
def clock_gettime(clk_id): # real signature unknown; restored from __doc__
"""
clock_gettime(clk_id) -> floating point number
Return the time of the specified clock clk_id.
"""
return 0.0
（5）clock_settime(clk_id,time)
def clock_settime(clk_id, time): # real signature unknown; restored from __doc__
"""
clock_settime(clk_id, time)
Set the time of the specified clock clk_id.
"""
pass
（6）ctime(seconds=None)
def ctime(seconds=None): # known case of time.ctime
"""
ctime(seconds) -> string
Convert a time in seconds since the Epoch to a string in local time.
This is equivalent to asctime(localtime(seconds)). When the time tuple is
not present, current time as returned by localtime() is used.
"""
return ""
ctime()返回系统当前的时间：
>>> time.ctime()
'Sun May 28 13:55:39 2017'
（7）get_clock_info(name)
def get_clock_info(name): # real signature unknown; restored from __doc__
"""
get_clock_info(name: str) -> dict
Get information of the specified clock.
"""
return {}
（8）gmtime(seconds=None)
def gmtime(seconds=None): # real signature unknown; restored from __doc__
"""
gmtime([seconds]) -> (tm_year, tm_mon, tm_mday, tm_hour, tm_min,
tm_sec, tm_wday, tm_yday, tm_isdst)
Convert seconds since the Epoch to a time tuple expressing UTC (a.k.a.
GMT). When 'seconds' is not passed in, convert the current time instead.
If the platform supports the tm_gmtoff and tm_zone, they are available as
attributes only.
"""
pass
gmtime(seconds=None)返回对应的时间格式，time.struct_time。
>>> time.gmtime()
time.struct_time(tm_year=2017, tm_mon=5, tm_mday=28, tm_hour=6, tm_min=1, tm_sec=28, tm_wday=6, tm_yday=148, tm_isdst=0)
（9）localtime(seconds=None) def localtime(seconds=None): # real signature unknown; restored from __doc__
"""
localtime([seconds]) -> (tm_year,tm_mon,tm_mday,tm_hour,tm_min,
tm_sec,tm_wday,tm_yday,tm_isdst)
Convert seconds since the Epoch to a time tuple expressing local time.
When 'seconds' is not passed in, convert the current time instead.
"""
pass
localtime()返回时间time.struct_time格式的日期。
>>> time.localtime()
time.struct_time(tm_year=2017, tm_mon=5, tm_mday=28, tm_hour=14, tm_min=3, tm_sec=58, tm_wday=6, tm_yday=148, tm_isdst=0)
（10）mktime()
def mktime(p_tuple): # real signature unknown; restored from __doc__
"""
mktime(tuple) -> floating point number
Convert a time tuple in local time to seconds since the Epoch.
Note that mktime(gmtime(0)) will not generally return zero for most
time zones; instead the returned value will either be equal to that
of the timezone or altzone attributes on the time module.
"""
return 0.0
（11）monotonic()
def monotonic(): # real signature unknown; restored from __doc__
"""
monotonic() -> float
Monotonic clock, cannot go backward.
"""
return 0.0
>>> time.monotonic()
27333.713613735
（12）perf_counter()
def perf_counter(): # real signature unknown; restored from __doc__
"""
perf_counter() -> float
Performance counter for benchmarking.
"""
return 0.0
>>> time.perf_counter()
27418.099319872
（13）process_time()
def process_time(): # real signature unknown; restored from __doc__
"""
process_time() -> float
Process time for profiling: sum of the kernel and user-space CPU time.
"""
return 0.0
>>> time.process_time()
0.521978947
（14）sleep(seconds)
def sleep(seconds): # real signature unknown; restored from __doc__
"""
sleep(seconds)
Delay execution for a given number of seconds. The argument may be
a floating point number for subsecond precision.
"""
pass
time.sleep(seconds)是程序停止运行一段时间。休眠。例如time.sleep(10)代表程序停止等待10秒钟。
（15）strftime(format,p_tuple=None)
def strftime(format, p_tuple=None): # real signature unknown; restored from __doc__
"""
strftime(format[, tuple]) -> string
Convert a time tuple to a string according to a format specification.
See the library reference manual for formatting codes. When the time tuple
is not present, current time as returned by localtime() is used.
Commonly used format codes:
%Y Year with century as a decimal number.
%m Month as a decimal number [01,12].
%d Day of the month as a decimal number [01,31].
%H Hour (24-hour clock) as a decimal number [00,23].
%M Minute as a decimal number [00,59].
%S Second as a decimal number [00,61].
%z Time zone offset from UTC.
%a Locale's abbreviated weekday name.
%A Locale's full weekday name.
%b Locale's abbreviated month name.
%B Locale's full month name.
%c Locale's appropriate date and time representation.
%I Hour (12-hour clock) as a decimal number [01,12].
%p Locale's equivalent of either AM or PM.
Other codes may be available on your platform. See documentation for
the C library strftime function.
"""
return ""
strftime(format,p_tuple)将时间进行格式转换，只能转换localtime()和gmtime()的struct_time格式时间情况；
>>> time.strftime("%Y-%m-%d %p",time.localtime())
'2017-05-28 PM'
>>> time.strftime("%Y-%m-%d %I:%M:%S%p",time.localtime())
'2017-05-28 02:23:21PM'
日期格式的转换，只能转换struct_time的格式；
>>> time.strftime("%a",time.localtime()) %a返回星期的简写
'Sun'
>>> time.strftime("%A",time.localtime()) %A返回日期的全拼
'Sunday'
（16）strptime(string,format)
def strptime(string, format): # real signature unknown; restored from __doc__
"""
strptime(string, format) -> struct_time
Parse a string to a time tuple according to a format specification.
See the library reference manual for formatting codes (same as
strftime()).
Commonly used format codes:
%Y Year with century as a decimal number.
%m Month as a decimal number [01,12].
%d Day of the month as a decimal number [01,31].
%H Hour (24-hour clock) as a decimal number [00,23].
%M Minute as a decimal number [00,59].
%S Second as a decimal number [00,61].
%z Time zone offset from UTC.
%a Locale's abbreviated weekday name.
%A Locale's full weekday name.
%b Locale's abbreviated month name.
%B Locale's full month name.
%c Locale's appropriate date and time representation.
%I Hour (12-hour clock) as a decimal number [01,12].
%p Locale's equivalent of either AM or PM.
Other codes may be available on your platform. See documentation for
the C library strftime function.
"""
return struct_time
strptime(string,format)将字符串的日期类型转化为struct_time类型。
>>> time.strptime("2017-5-18","%Y-%m-%d")
time.struct_time(tm_year=2017, tm_mon=5, tm_mday=18, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=138, tm_isdst=-1)
（17）time()
def time(): # real signature unknown; restored from __doc__
"""
time() -> floating point number
Return the current time in seconds since the Epoch.
Fractions of a second may be present if the system clock provides them.
"""
return 0.0
time()返回浮点数。
>>> time.time()
1495953536.3603268
（18）tzset()
def tzset(): # real signature unknown; restored from __doc__
"""
tzset()
Initialize, or reinitialize, the local timezone to the value stored in
os.environ['TZ']. The TZ environment variable should be specified in
standard Unix timezone format as documented in the tzset man page
(eg. 'US/Eastern', 'Europe/Amsterdam'). Unknown timezones will silently
fall back to UTC. If the TZ environment variable is not set, the local
timezone is set to the systems best guess of wallclock time.
Changing the TZ environment variable without calling tzset *may* change
the local timezone used by methods such as localtime, but this behaviour
should not be relied on.
"""
pass
datetime模块
"""
import datetime
datetime.date：表示日期的类。常用的属性有year, month, day
datetime.time：表示时间的类。常用的属性有hour, minute, second, microsecond
datetime.datetime：表示日期时间
datetime.timedelta：表示时间间隔，即两个时间点之间的长度
timedelta([days[, seconds[, microseconds[, milliseconds[, minutes[, hours[, weeks]]]]]]])
strftime("%Y-%m-%d")
"""
（1）datetime.date：表示日期的类。常用的属性有year,month,day
>>> datetime.date.today()
datetime.date(2017, 5, 28)
返回日期的格式情况，包含的属性有year(年)、month(月)、日(day)。
（2）datetime.time:表示时间的类。常用的属性有hour,minute,second,microsecond
>>> datetime.time(12,30,59,99)
datetime.time(12, 30, 59, 99)
返回日期时间的格式情况，如datetime.time()
（3）datetime.datetime：表示日期时间
>>> datetime.datetime(2016,5,12,7,59,59,99)
datetime.datetime(2016, 5, 12, 7, 59, 59, 99)
>>> datetime.datetime.now()
datetime.datetime(2017, 5, 28, 15, 34, 1, 105235)
>>> datetime.datetime.today()
datetime.datetime(2017, 5, 28, 15, 35, 9, 384407)
（4）datetime.timedelta：表示时间间隔，两个时间点之间的长度
（5）timedelta([days[, seconds[, microseconds[, milliseconds[, minutes[, hours[, weeks]]]]]]])
（6）strftime("%Y-%m-%d")
实例：
>>> now_date = datetime.datetime.now() + datetime.timedelta(days=10) （1）比现在日期多十天
>>> now_date
datetime.datetime(2017, 6, 7, 15, 37, 7, 936368)
>>> str_to_date = datetime.datetime.strptime("16/11/17 16:30","%d/%m/%y %H:%M") （2）将字符串时间格式化转化为时间
>>> str_to_date
datetime.datetime(2017, 11, 16, 16, 30)
>>> new_date = datetime.datetime.now() + datetime.timedelta(hours=-10) （3）比现在时间少10个小时
>>> new_date
datetime.datetime(2017, 5, 28, 20, 1, 11, 805686)
