time

1. 时间戳

• 一个时间表示，根据不同语言，可以是整数或者浮点数
• 是从 1970年1月1日0时0分0秒 到现在经历的秒数
• 如果表示的时间是 1970年以前 或者 太遥远的未来，可能出现异常
• 32位操作系统 能够支持到 2038年

2. UTC 时间

• UTC 又称 世界协调时间，以英国的格林尼治天文所在地区的时间作为参考的时间，也叫做 世界标准时间
• 中国时间是 UTC+8 东八区

3. 夏令时

• 在夏天的时候将时间调快一小时
• 本意是督促大家早睡早起节省蜡烛，每天变成 25 个小时，本质没变还是 24 小时

4. 时间元组

• 一个包含时间内容的普通元组

5. 举例

• 必要的准备工作

>>> import time

5.1 例子1

• time.timezone
  • 当前时区和 UTC 时间相差的秒数
  • 在没有夏令时的情况下，中（零）时区与东八区相差 -28800s
• time.altzone
  • 获取当前时区与 UTC 时间相差的秒数
  • 在有夏令时的情况下，中（零）时区与东八区相差 -32400s
• time.daylight
  • 测当前是否是夏令时时间状态
  • 0 表示是

>>> time.timezone
-28800
>>> time.altzone
-32400
>>> time.daylight
0

例子2

• time.time
  • 时间戳
• time.localtime
  • Convert seconds since the Epoch to a time tuple expressing local time.
  • When ‘seconds‘ is not passed in, convert the current time instead.

>>> time.time()
1576070236.623945
>>> time.localtime()
time.struct_time(tm_year=2019, tm_mon=12, tm_mday=11, tm_hour=21, tm_min=17, tm_sec=29, tm_wday=2, tm_yday=345, tm_isdst=0)
>>> t = time.localtime()
>>> t.tm_hour
21

例子3

• time.asctime
  • 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.

>>> t1 = time.localtime()
>>> t2 = time.asctime(t1)
>>> type(t2)
<class 'str'>
>>> t2
'Wed Dec 11 21:18:03 2019'

例子4

• time.ctime
  • 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.

>>> t = time.ctime()
>>> type(t)
<class 'str'>
>>> t
'Wed Dec 11 21:19:02 2019'

例子5

• time.mktime
  • 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.

>>> lt = time.localtime()
>>> ts = time.mktime(lt)
>>> type(ts)
<class 'float'>
>>> ts
1576070374.0

例子6

• time.clock
  • 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.
• time.sleep
  • Delay execution for a given number of seconds.
  • The argument may be a floating point number for subsecond precision.

# run in ipython
t0 = time.clock()
time.sleep(3)
t1 = time.clock()
print(t1 - t0)

>>>

...
DeprecationWarning: time.clock has been deprecated in Python 3.3 and will be removed from Python 3.8: use time.perf_counter or time.process_time instead
  """Entry point for launching an IPython kernel.
3.0017606999999984
...
This is separate from the ipykernel package so we can avoid doing imports until

• 既然官方说了，那就用 time.perf_counter 或 time.process_time 喽

例子7

• strftime
  • Convert a time tuple to a string according to a format specification.
  • When the time tuple is not present, current time as returned by localtime() is used.
• help(time.strftime)

• 补充

>>> lt = time.localtime()
>>> ft = time.strftime("%Y-%m-%d %H:%M", lt)
>>> ft
'2019-12-11 21:20'

[Python3] 027 常用模块 time

原文：https://www.cnblogs.com/yorkyu/p/12025286.html