Python模块之time&datetime

time&datetime模块

　　Python提供了多个内置模块用于操作日期时间，例如：calendar，time，datetime。time模块它提供的接口与C标准库time.h基本一致。相比于time模块，datetime模块的接口则更直观、更容易调用。

>>> import time
>>> import datetime

>>> print(time.clock()) 　　　　　　　　# 返回处理器时间,3.3开始已废弃
2.199715466804369e-06
>>> print(time.process_time()) 　　　　# 返回处理器时间,3.3开始已废弃
6.9888448
>>> print(time.time()) 　　　　　　　　 # 返回当前系统时间戳
1465222058.1238248
>>> print(time.ctime()) 　　　　　　　　# 输出Tue Jan 26 18:23:48 2016 ,当前系统时间
Mon Jun  6 22:07:38 2016
>>> print(time.ctime(time.time()-86640))  # 将时间戳转为字符串格式
Sun Jun  5 22:03:38 2016
>>> print(time.gmtime(time.time()-86640)) # 将时间戳转换成struct_time格式
time.struct_time(tm_year=2016, tm_mon=6, tm_mday=5, tm_hour=14, tm_min=3, tm_sec=38, tm_wday=6, tm_yday=157, tm_isdst=0)
>>> print(time.localtime(time.time()-86640)) # 将时间戳转换成struct_time格式,但返回的本地时间
time.struct_time(tm_year=2016, tm_mon=6, tm_mday=5, tm_hour=22, tm_min=3, tm_sec=38, tm_wday=6, tm_yday=157, tm_isdst=0)
>>> print(time.mktime(time.localtime()))     # 与time.localtime()功能相反,将struct_time格式转回成时间戳格式
1465222059.0

#time.sleep(4) #sleep
>>> print(time.strftime("%Y-%m-%d %H:%M:%S",time.gmtime()) ) # 将struct_time格式转成指定的字符串格式
2016-06-06 14:07:39
>>> print(time.strptime("2016-01-28","%Y-%m-%d") ) 　　　　　　# 将字符串格式转换成struct_time格式
time.struct_time(tm_year=2016, tm_mon=1, tm_mday=28, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=28, tm_isdst=-1)

#datetime module
>>>print(datetime.date.today()) 　　# 输出格式 2016-01-26
2016-06-06
>>> print(datetime.date.fromtimestamp(time.time()-864400) ) #2016-01-16 将时间戳转成日期格式
2016-05-27
>>> current_time = datetime.datetime.now()
>>> print(current_time) 　　　　　　　　  # 输出2016-01-26 19:04:30.335935
2016-06-06 22:07:40.183942
>>> print(current_time.timetuple()) 　　# 返回struct_time格式
time.struct_time(tm_year=2016, tm_mon=6, tm_mday=6, tm_hour=22, tm_min=7, tm_sec=40, tm_wday=0, tm_yday=158, tm_isdst=-1)

# datetime.replace([year[, month[, day[, hour[, minute[, second[, microsecond[, tzinfo]]]]]]]])
>>>print(current_time.replace(2014,9,12)) 　　　　# 输出2014-09-12 19:06:24.074900,返回当前时间,但指定的值将被替换
2014-09-12 22:07:40.183942
>>>str_to_date = datetime.datetime.strptime("21/11/06 16:30", "%d/%m/%y %H:%M") 　　# 将字符串转换成日期格式
>>> new_date = datetime.datetime.now() + datetime.timedelta(days=10) 　　　　　　　　 # 比现在加10天
>>> print(new_date)
2016-06-16 22:11:14.076176
>>> new_date = datetime.datetime.now() + datetime.timedelta(days=-10)               # 比现在减10天
>>> print(new_date)
2016-05-27 22:11:14.339191
>>> new_date = datetime.datetime.now() + datetime.timedelta(hours=-10)              # 比现在减10小时
>>> print(new_date)
2016-06-06 12:11:14.608207
>>> new_date = datetime.datetime.now() + datetime.timedelta(seconds=120)            # 比现在+120s
>>> print(new_date)
2016-06-06 22:13:14.880222

%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.