python之常用标准库-时间

1.time

• 时间戳：它代表了从格林尼治时间1970年01月01日00时00分00秒（即北京时间的1970年01月01日08时00分00秒）开始到现在经过的总秒数。

• struct_time:用一个包含9个序列的元组组成（tm_year=2024, tm_mon=1, tm_mday=26, tm_hour=2, tm_min=49, tm_sec=56, tm_wday=4, tm_yday=26, tm_isdst=-1）,参数通过tuple展示

• 字符串时间：多种格式的字符串时间 2024-01-26 03:00:29；Fri Jan 26 03:00:28 2024

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1.1.struct_time

• 时间戳转struct_time 

            localtime(时间戳))--》返回+8h的struct_time，时间戳为空时，默认为当前时间

            gmtime(时间戳))--》返回utc的struct_time,时间戳为空时，默认返回utc的struct_time

• 字符串转struct_time

        strptime('2024-01-26 11:44:45','%Y-%m-%d %H:%M:%S)--》返回字符串对应的struct_time

• struct_time([2024,01,26,11,44,45,4,26,0]) --》自身赋值

#!/usr/bin/python
#常用模块学习
import time ,datetime
# print(dir(time))
#structime
print(time.localtime())#将时间戳转为struct_time格式 +8小时
print(time.gmtime(1706234296))#将时间戳转为struct_time格式的UTC时间
print(time.strptime('2024-01-26 02:49:56','%Y-%m-%d %H:%M:%S'))#字符串转为指定格式struct_time
print(time.struct_time([2024,1,26,14,54,34,5,26,0]))#给struct_time赋值

1.2.时间戳

• time（）--》获取当前时间戳
• mktime(stuple)--》将struct_time转为时间戳

#!/usr/bin/python
#常用模块学习
import time ,datetime
print(time.mktime(time.gmtime(1706234296)))#将struct_time转为时间戳
print(time.time())#时间戳

1.3.字符串

• strftime('%Y-%m-%s %H:%M:%S','时间戳')
• ctime(时间戳）
• asctime(tuple)

#!/usr/bin/python
#常用模块学习
import time ,datetime
#字符串
print(time.asctime(time.gmtime()))#将struct_time转为字符串e.g. 'Sat Jun 06 16:26:11 1998'
print(time.ctime(1706234296))#将时间戳转为字符串e.g. 'Sat Jun 06 16:26:11 1998'
print(time.strftime('%Y-%m-%d %H:%M:%S',time.gmtime()))#struct_time转为指定格式字符串

1.4.sleep

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
翻译：延迟给定的秒数执行，参数可以时浮点数

#!/usr/bin/python
#常用模块学习
import time ,datetime
print(time.sleep(0.40))#延迟执行参数

1.5.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
翻译：分析进程处理时间：包含内核和cpu

#!/usr/bin/python
#常用模块学习
import time ,datetime
print(time.process_time())#用于分析进程时间浮点数

1.6.thread_time

def thread_time(): # real signature unknown; restored from __doc__
    """
    thread_time() -> float
    
    Thread time for profiling: sum of the kernel and user-space CPU time.
    """
    return 0.0
翻译：分析线程处理时间：包含内核和cpu

2.datetime

2.1 datetime.datetime.now()

def now(cls, tz=None):
    "Construct a datetime from time.time() and optional time zone info."
    t = _time.time()
    return cls.fromtimestamp(t, tz)
翻译：通过时间戳time.time()和一个可选时间区，构建一个日期；打印当前时间

2.2 datetime.date.fromtimestamp(时间戳)

def fromtimestamp(cls, t):
    "Construct a date from a POSIX timestamp (like time.time())."
    y, m, d, hh, mm, ss, weekday, jday, dst = _time.localtime(t)
    return cls(y, m, d)
翻译：通过一个时间戳构建一个日期；打印当前日期 2024-01-26

2.3 datetime.datetime.fromtimestamp(时间戳)

def fromtimestamp(cls, t, tz=None):
    """Construct a datetime from a POSIX timestamp (like time.time()).

    A timezone info object may be passed in as well.
    """
    _check_tzinfo_arg(tz)

    return cls._fromtimestamp(t, tz is not None, tz)
翻译：通过一个时间戳构建一个日期时间，打印日期时间如2024-01-26 11：26：32

2.4 datetime.datetime.now()+datetime.timedelta()

if sys.version_info >= (3, 6):
    def __init__(self, days: float = ..., seconds: float = ..., microseconds: float = ...,
                 milliseconds: float = ..., minutes: float = ..., hours: float = ...,
                 weeks: float = ..., *, fold: int = ...) -> None: ...
翻译：就是在now基础上加减给定参数值（正数为加，负数为减）

#!/usr/bin/python
#常用模块学习
import time ,datetime
print(datetime.datetime.now())
print(datetime.date.fromtimestamp(1706234296)) #时间戳转日期
print(datetime.datetime.fromtimestamp(1706234296))#时间戳转日期时间格式
print(datetime.datetime.now()+datetime.timedelta(5))#当前时间加5天
print(datetime.datetime.now()+datetime.timedelta(-5))#当前时间减5天
print(datetime.datetime.now()+datetime.timedelta(days=-5,hours=3,minutes=30))#当前时间减5天加3小时30分钟