1.有关时间的基本知识点
（1）表示时间的方式
a）时间戳：timestamp
b）格式化的时间字符串：Format string
c）共9个元素的元组：struct_time
（2）时间表示方式的说明
a）UTC（Coordinated Universal Time，世界协调时）：亦即格林威治天文时间，世界标准时间。在中国为UTC+8。DST（Daylight Saving Time）即夏令时。
b）时间戳：表示的是从1970年1月1日00:00:00开始按秒计算的偏移量。我们运行“type(time.time())”，返回的是float类型。返回时间戳方式的函数主要有time()，clock()等。
c）元组方式：struct_time元组共有9个元素，返回struct_time的函数主要有gmtime()，localtime()，strptime()。
2.time模块详解
NAME
time - This module provides various functions to manipulate time values.
DESCRIPTION
There are two standard representations of time. One is the number
of seconds since the Epoch, in UTC (a.k.a. GMT). It may be an integer
or a floating point number (to represent fractions of seconds).
The Epoch is system-defined; on Unix, it is generally January 1st, 1970.
The actual value can be retrieved by calling gmtime(0).
The other representation is a tuple of 9 integers giving local time.
The tuple items are:
year (including century, e.g. 1998) # tm_year
month (1-12) # tm_mon
day (1-31) # tm_mday
hours (0-23) # tm_hour
minutes (0-59) # tm_min
seconds (0-59) # tm_sec
weekday (0-6, Monday is 0) # tm_wday
Julian day (day in the year, 1-366) # tm_yday
DST (Daylight Savings Time) flag (-1, 0 or 1) # tm_isdst
If the DST flag is 0, the time is given in the regular time zone;
if it is 1, the time is given in the DST time zone;
if it is -1, mktime() should guess based on the date and time.
CLASSES
builtins.tuple(builtins.object)
struct_time
class struct_time(builtins.tuple)
| The time value as returned by gmtime(), localtime(), and strptime(), and
| accepted by asctime(), mktime() and strftime(). May be considered as a
| sequence of 9 integers.
|
| Note that several fields' values are not the same as those defined by
| the C language standard for struct tm. For example, the value of the
| field tm_year is the actual year, not year - 1900. See individual
| fields' descriptions for details.
|
| Method resolution order:
| struct_time
| builtins.tuple
| builtins.object
|
| Methods defined here:
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __reduce__(...)
| helper for pickle
|
| __repr__(self, /)
| Return repr(self).
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| tm_gmtoff
| offset from UTC in seconds
|
| tm_hour
| hours, range [0, 23]
|
| tm_isdst
| 1 if summer time is in effect, 0 if not, and -1 if unknown
|
| tm_mday
| day of month, range [1, 31]
|
| tm_min
| minutes, range [0, 59]
|
| tm_mon
| month of year, range [1, 12]
|
| tm_sec
| seconds, range [0, 61])
|
| tm_wday
| day of week, range [0, 6], Monday is 0
|
| tm_yday
| day of year, range [1, 366]
|
| tm_year
| year, for example, 1993
|
| tm_zone
| abbreviation of timezone name
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| n_fields = 11
|
| n_sequence_fields = 9
|
| n_unnamed_fields = 0
|
| ----------------------------------------------------------------------
| Methods inherited from builtins.tuple:
|
| __add__(self, value, /)
| Return self+value.
|
| __contains__(self, key, /)
| Return key in self.
|
| __eq__(self, value, /)
| Return self==value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __getitem__(self, key, /)
| Return self[key].
|
| __getnewargs__(...)
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __iter__(self, /)
| Implement iter(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __len__(self, /)
| Return len(self).
|
| __lt__(self, value, /)
| Return self<value.
|
| __mul__(self, value, /)
| Return self*value.n
|
| __ne__(self, value, /)
| Return self!=value.
|
| __rmul__(self, value, /)
| Return self*value.
|
| count(...)
| T.count(value) -> integer -- return number of occurrences of value
|
| index(...)
| T.index(value, [start, [stop]]) -> integer -- return first index of value.
| Raises ValueError if the value is not present.
FUNCTIONS
asctime(...)
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.
clock(...)"""
这个需要注意，在不同的系统上含义不同。在UNIX系统上，它返回的是“进程时间”，它是用秒表示的浮点数（时间戳）。而在WINDOWS中，第一次调用，返回的是进程运行的实际时间。而第二次之后的调用是自第一次调用以后到现在的运行时间。（实际上是以WIN32上QueryPerformanceCounter()为基础，它比毫秒表示更为精确）
"""
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.
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.
get_clock_info(...)
get_clock_info(name: str) -> dict
Get information of the specified clock.
gmtime(...)
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.
localtime(...)
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.
mktime(...)
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.
monotonic(...)
monotonic() -> float
Monotonic clock, cannot go backward.
perf_counter(...)
perf_counter() -> float
Performance counter for benchmarking.
process_time(...)
process_time() -> float
Process time for profiling: sum of the kernel and user-space CPU time.# 分析的进程时间:内核和用户空间CPU时间的总和
sleep(...)
sleep(seconds)
Delay execution for a given number of seconds. The argument may be
a floating point number for subsecond precision.
strftime(...)
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.
strptime(...)
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.
time(...)
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.
DATA
altzone = -32400
daylight = 0
timezone = -28800
tzname = ('Öйú±ê׼ʱ¼ä', 'ÖйúÏÄÁîʱ')
FILE
(built-in)
3.datetime模块详解
NAME
datetime - Fast implementation of the datetime type.
CLASSES
builtins.object
date
datetime
time
timedelta
tzinfo
timezone
class date(builtins.object)
| date(year, month, day) --> date object
|
| Methods defined here:
|
| __add__(self, value, /)
| Return self+value.
|
| __eq__(self, value, /)
| Return self==value.
|
| __format__(...)
| Formats self with strftime.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __lt__(self, value, /)
| Return self<value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __radd__(self, value, /)
| Return value+self.
|
| __reduce__(...)
| __reduce__() -> (cls, state)
|
| __repr__(self, /)
| Return repr(self).
|
| __rsub__(self, value, /)
| Return value-self.
|
| __str__(self, /)
| Return str(self).
|
| __sub__(self, value, /)
| Return self-value.
|
| ctime(...)
| Return ctime() style string. # 返回格式化字符串
|
| fromordinal(...) from builtins.type
| int -> date corresponding to a proleptic Gregorian ordinal.
|
| fromtimestamp(...) from builtins.type # 根据给定的时间戳，返回一个date对象
| timestamp -> local date from a POSIX timestamp (like time.time()).
|
| isocalendar(...)
| Return a 3-tuple containing ISO year, week number, and weekday.
|
| isoformat(...) # 返回格式化字符串：YYYY-MM-DD.
| Return string in ISO 8601 format, YYYY-MM-DD.
|
| isoweekday(...) # 返回给定日期的星期
| Return the day of the week represented by the date.
| Monday == 1 ... Sunday == 7
|
| replace(...) # 替换给定日期（year，month，day），不改变原日期
| Return date with new specified fields.
|
| strftime(...) # 按照给定的format进行格式化
| format -> strftime() style string.
|
| timetuple(...) # 返回时间对应的元组
| Return time tuple, compatible with time.localtime().
|
| today(...) from builtins.type # 返回一个date对象，等价于datetime.date.from
| Current date or datetime: same as self.__class__.fromtimestamp(time.time()).
|
| toordinal(...) # 返回从1970年1月1号到指定日期的总天数
| Return proleptic Gregorian ordinal. January 1 of year 1 is day 1.
|
| weekday(...) # 返回日期对应的星期
| Return the day of the week represented by the date.
| Monday == 0 ... Sunday == 6
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| day
|
| month
|
| year
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| max = datetime.date(9999, 12, 31)
|
| min = datetime.date(1, 1, 1)
|
| resolution = datetime.timedelta(1)
class datetime(date)
| datetime(year, month, day[, hour[, minute[, second[, microsecond[,tzinfo]]]]])
|
| The year, month and day arguments are required. tzinfo may be None, or an
| instance of a tzinfo subclass. The remaining arguments may be ints.
|
| Method resolution order:
| datetime
| date
| builtins.object
|
| Methods defined here:
|
| __add__(self, value, /)
| Return self+value.
|
| __eq__(self, value, /)
| Return self==value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __lt__(self, value, /)
| Return self<value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __radd__(self, value, /)
| Return value+self.
|
| __reduce__(...)
| __reduce__() -> (cls, state)
|
| __reduce_ex__(...)
| __reduce_ex__(proto) -> (cls, state)
|
| __repr__(self, /)
| Return repr(self).
|
| __rsub__(self, value, /)
| Return value-self.
|
| __str__(self, /)
| Return str(self).
|
| __sub__(self, value, /)
| Return self-value.
|
| astimezone(...)
| tz -> convert to local time in new timezone tz
|
| combine(datetime.date(), datetime.time()) from builtins.type # 将date对象和time对象进行合并，生成datetime对象
| date, time -> datetime with same date and time fields
|
| ctime(...) # 返回格式化字符串
| Return ctime() style string.
|
| date(...) # 返回datetime对象的year,month,day
| Return date object with same year, month and day.
|
| dst(...)
| Return self.tzinfo.dst(self).
|
| fromtimestamp(...) from builtins.type # 根据给定的时间戳返回datetime对象
| timestamp[, tz] -> tz's local time from POSIX timestamp.
|
| isoformat(...) # 返回格式化字符串：YYYY-MM-DDT[HH[:MM[:SS[.mmm[uuu]]]]][+HH:MM]
| [sep] -> string in ISO 8601 format, YYYY-MM-DDT[HH[:MM[:SS[.mmm[uuu]]]]][+HH:MM].
| sep is used to separate the year from the time, and defaults to 'T'.
| timespec specifies what components of the time to include (allowed values are 'auto', 'hours', 'minutes', 'seconds', 'milliseconds', and 'microseconds').
|
| now(tz=None) from builtins.type # 返回当前系统时间的datetime对象
| Returns new datetime object representing current time local to tz.
|
| tz
| Timezone object.
|
| If no tz is specified, uses local timezone.
|
| replace(...) # 替换给定datetime对象内容，不改变原内容
| Return datetime with new specified fields.
|
| strptime(...) from builtins.type # 将给定str转换成对应的format格式的datetime对象
| string, format -> new datetime parsed from a string (like time.strptime()).
|
| time(...) # datetime.datetime对象输出对应时间的time对象
| Return time object with same time but with tzinfo=None.
|
| timestamp(...) # 返回datetime对象的时间戳
| Return POSIX timestamp as float.
|
| timetuple(...) # 返回datetime对象的struct_time元组形式
| Return time tuple, compatible with time.localtime().
|
| timetz(...)
| Return time object with same time and tzinfo.
|
| tzname(...)
| Return self.tzinfo.tzname(self).
|
| utcfromtimestamp(timestamp) from builtins.type # 从POSIX时间戳构造一个朴素的UTC日期时间
| Construct a naive UTC datetime from a POSIX timestamp.
|
| utcnow(...) from builtins.type # 返回当前时间的UTC日期时间
| Return a new datetime representing UTC day and time.
|
| utcoffset(...)
| Return self.tzinfo.utcoffset(self).
|
| utctimetuple(...) # 返回UTC时间元组，与time.localtime()兼容
| Return UTC time tuple, compatible with time.localtime().
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| fold
|
| hour
|
| microsecond
|
| minute
|
| second
|
| tzinfo
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| max = datetime.datetime(9999, 12, 31, 23, 59, 59, 999999)
|
| min = datetime.datetime(1, 1, 1, 0, 0)
|
| resolution = datetime.timedelta(0, 0, 1)
|
| ----------------------------------------------------------------------
| Methods inherited from date:
|
| __format__(...)
| Formats self with strftime.
|
| fromordinal(...) from builtins.type
| int -> date corresponding to a proleptic Gregorian ordinal.
|
| isocalendar(...) # 返回元组：（年，周，一周的第几天）
| Return a 3-tuple containing ISO year, week number, and weekday.
|
| (isoweekday...) # 返回当前日期是当前周的第几天
| Return the day of the week represented by the date.
| Monday == 1 ... Sunday == 7
|
| strftime(...) # 将datetime对象转换成固定format字符串
| format -> strftime() style string.
|
| today(...) from builtins.type # 返回当前日期
| Current date or datetime: same as self.__class__.fromtimestamp(time.time()).
|
| toordinal(...) # 生成时间戳
| Return proleptic Gregorian ordinal. January 1 of year 1 is day 1.
|
| weekday(...) # 返回日期是一周中的第几天
| Return the day of the week represented by the date.
| Monday == 0 ... Sunday == 6
|
| ----------------------------------------------------------------------
| Data descriptors inherited from date:
|
| day
|
| month
|
| year
class time(builtins.object)
| time([hour[, minute[, second[, microsecond[, tzinfo]]]]]) --> a time object
|
| All arguments are optional. tzinfo may be None, or an instance of
| a tzinfo subclass. The remaining arguments may be ints.
|
| Methods defined here:
|
| __eq__(self, value, /)
| Return self==value.
|
| __format__(...)
| Formats self with strftime.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __lt__(self, value, /)
| Return self<value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __reduce__(...)
| __reduce__() -> (cls, state)
|
| __reduce_ex__(...)
| __reduce_ex__(proto) -> (cls, state)
|
| __repr__(self, /)
| Return repr(self).
|
| __str__(self, /)
| Return str(self).
|
| dst(...)
| Return self.tzinfo.dst(self).
|
| isoformat(...) # 输出符合 ISO 8601格式的字符串
| Return string in ISO 8601 format, [HH[:MM[:SS[.mmm[uuu]]]]][+HH:MM].
|
| timespec specifies what components of the time to include.
|
| replace(...) # 通过新hour,minute,second生成新的datetime.time对象
| Return time with new specified fields.
|
| strftime(...) # 生成对应format的字符串
| format -> strftime() style string.
|
| tzname(...)
| Return self.tzinfo.tzname(self).
|
| utcoffset(...)
| Return self.tzinfo.utcoffset(self).
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| fold
|
| hour
|
| microsecond
|
| minute
|
| second
|
| tzinfo
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| max = datetime.time(23, 59, 59, 999999)
|
| min = datetime.time(0, 0)
|
| resolution = datetime.timedelta(0, 0, 1)
class timedelta(builtins.object)
| Difference between two datetime values. ------>>> "主要用于时间的加减"
|
| Methods defined here:
|
| __abs__(self, /)
| abs(self)
|
| __add__(self, value, /)
| Return self+value.
|
| __bool__(self, /)
| self != 0
|
| __divmod__(self, value, /)
| Return divmod(self, value).
|
| __eq__(self, value, /)
| Return self==value.
|
| __floordiv__(self, value, /)
| Return self//value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __lt__(self, value, /)
| Return self<value.
|
| __mod__(self, value, /)
| Return self%value.
|
| __mul__(self, value, /)
| Return self*value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __neg__(self, /)
| -self
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __pos__(self, /)
| +self
|
| __radd__(self, value, /)
| Return value+self.
|
| __rdivmod__(self, value, /)
| Return divmod(value, self).
|
| __reduce__(...)
| __reduce__() -> (cls, state)
|
| __repr__(self, /)
| Return repr(self).
|
| __rfloordiv__(self, value, /)
| Return value//self.
|
| __rmod__(self, value, /)
| Return value%self.
|
| __rmul__(self, value, /)
| Return value*self.
|
| __rsub__(self, value, /)
| Return value-self.
|
| __rtruediv__(self, value, /)
| Return value/self.
|
| __str__(self, /)
| Return str(self).
|
| __sub__(self, value, /)
| Return self-value.
|
| __truediv__(self, value, /)
| Return self/value.
|
| total_seconds(...)
| Total seconds in the duration.
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| days
| Number of days.
|
| microseconds
| Number of microseconds (>= 0 and less than 1 second).
|
| seconds
| Number of seconds (>= 0 and less than 1 day).
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| max = datetime.timedelta(999999999, 86399, 999999)
|
| min = datetime.timedelta(-999999999)
|
| resolution = datetime.timedelta(0, 0, 1)
class timezone(tzinfo)
| Fixed offset from UTC implementation of tzinfo. ------>>> "主要用来转换时区的"
|
| Method resolution order:
| timezone
| tzinfo
| builtins.object
|
| Methods defined here:
|
| __eq__(self, value, /)
| Return self==value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getinitargs__(...)
| pickle support
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __lt__(self, value, /)
| Return self<value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __repr__(self, /)
| Return repr(self).
|
| __str__(self, /)
| Return str(self).
|
| dst(...)
| Return None.
|
| fromutc(...)
| datetime in UTC -> datetime in local time.
|
| tzname(...)
| If name is specified when timezone is created, returns the name. Otherwise returns offset as 'UTC(+|-)HH:MM'.
|
| utcoffset(...)
| Return fixed offset.
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| max = datetime.timezone(datetime.timedelta(0, 86340))
|
| min = datetime.timezone(datetime.timedelta(-1, 60))
|
| utc = datetime.timezone.utc
|
| ----------------------------------------------------------------------
| Methods inherited from tzinfo:
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __reduce__(...)
| -> (cls, state)
class tzinfo(builtins.object)
| Abstract base class for time zone info objects.
|
| Methods defined here:
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __reduce__(...)
| -> (cls, state)
|
| dst(...)
| datetime -> DST offset in minutes east of UTC.
|
| fromutc(...)
| datetime in UTC -> datetime in local time.
|
| tzname(...)
| datetime -> string name of time zone.
|
| utcoffset(...)
| datetime -> timedelta showing offset from UTC, negative values indicating West of UTC
DATA
MAXYEAR = 9999
MINYEAR = 1
datetime_CAPI = <capsule object "datetime.datetime_CAPI">
FILE
d:\anaconda\lib\datetime.py
4.格式参照
%a 本地（locale）简化星期名称
%A 本地完整星期名称
%b 本地简化月份名称
%B 本地完整月份名称
%c 本地相应的日期和时间表示
%d 一个月中的第几天（01 - 31）
%H 一天中的第几个小时（24小时制，00 - 23）
%I 第几个小时（12小时制，01 - 12）
%j 一年中的第几天（001 - 366）
%m 月份（01 - 12）
%M 分钟数（00 - 59）
%p 本地am或者pm的相应符
%S 秒（01 - 61）
%U 一年中的星期数。（00 - 53星期天是一个星期的开始。）第一个星期天之前的所有天数都放在第0周。
%w 一个星期中的第几天（0 - 6，0是星期天）
%W 和%U基本相同，不同的是%W以星期一为一个星期的开始。
%x 本地相应日期
%X 本地相应时间
%y 去掉世纪的年份（00 - 99）
%Y 完整的年份
%Z 时区的名字（如果不存在为空字符）
%% ‘%’字符5.程序实例
（1）time模块
import time
# 返回处理器时间
print(time.clock())
# 返回与utc时间的时间差,以秒计算
print(time.altzone)
# 返回时间格式"Fri Aug 19 11:14:16 2016" == 将时间元组转换成字符串
print(time.asctime())
# 返回本地时间[时间戳]的struct_time对象格式
print(time.localtime(time.time()))
# 返回utc时间的struct_time时间对象格式
print(time.gmtime(time.time()))
print("*" * 100)
# 将struct_time转换成"Fri Aug 19 11:14:16 2016"
print(time.asctime(time.localtime()))
# 将时间戳转换为格式化字符串"Fri Aug 19 11:14:16 2016"
print(time.ctime(time.time()))
# ----------------------------------------------------------------
# 将 日期字符串 转成 struct时间对象格式
string_2_struct = time.strptime("2016/05/22", "%Y/%m/%d")
print(string_2_struct)
print("*" * 100)
# 将struct时间对象转成时间戳
struct_2_stamp = time.mktime(string_2_struct)
print(struct_2_stamp)
print("*" * 100)
# ----------------------------------------------------------------
# 时间戳转换为字符串
print(time.strftime("%Y - %m - %d", time.gmtime(time.time())))
print(time.strftime("%Y - %m - %d", time.localtime()))（2）datetime模块
import datetime
import time
# datetime.datetime.now()相当于调用了datetime.datetime.fromtimestamp(time.time())
print(datetime.datetime.now())
print(datetime.datetime.fromtimestamp(time.time())) # <class 'datetime.datetime'>
# 当前时间加3天
print(datetime.datetime.now() + datetime.timedelta(3))
# 当前时间减3天
print(datetime.datetime.now() + datetime.timedelta(-3))
# 当前时间加3小时
print(datetime.datetime.now() + datetime.timedelta(hours=3))
# 当前时间加30分钟
print(datetime.datetime.now() + datetime.timedelta(minutes=30))
# datetime对象的时间替换
c_time = datetime.datetime.now()
print(c_time.replace(hour=2, minute=2))