python的内置模块time和datetime的方法详解以及使用(python内的time和datetime时间格式)

time内置模块的方法

1、time() 时间戳

time() -> floating point number  浮点数
Return the current time in seconds since the Epoch.
Fractions of a second may be present if the system clock provides them.

import time
print(time.time())
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
1528517838.7509072

这个时间戳是一个秒数，是从1970年凌晨开始算，到现在一共经历了多少秒

现在是2018年，减去1970年，是48年，

48*365*24*60*60=1513728000

哈哈算出来跟上面的差不多，这就是时间戳，每一秒都不一样

时间戳可以可以用来计算2个时间的减法，就是比如我下单的时候是一个时间戳，我支付成功再来一个时间戳，可以计算一下我下单到支付花了多少秒

2、localtime(seconds=None) 结构化时间-当地时间

得到的是一个结构化时间

Convert seconds since the Epoch to a time tuple expressing local time.
When 'seconds' is not passed in, convert the current time instead

import time
print(time.localtime())
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
time.struct_time(tm_year=2018, tm_mon=6, tm_mday=9, tm_hour=12, tm_min=36, tm_sec=7, tm_wday=5, tm_yday=160, tm_isdst=0)

那么我们就可以取出来具体的其中的具体的年份或者是时分秒，一周的第几天，一年的第几天

import time
a=time.localtime()
print(a.tm_year,a.tm_mon,a.tm_mday,a.tm_hour,":",a.tm_min,":",a.tm_sec)
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
2018 6 9 12 : 46 : 1

3、gmtime  也是结构化时间 世界标准化时间-UTC

时间标准时间，跟我们的时间差8个小时

4、mktime(p_tuple)

mktime(tuple) -> floating point number

将结构化时间转换成时间戳

import time
print(time.mktime(time.localtime()))
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
1528522939.0

5、strftime(format, p_tuple=None)

将结构化时间转化成字符串时间

%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. 

%X就代表时分秒

import time
print(time.strftime("%Y-%m-%d %X",time.localtime()))
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
2018-06-09 15:11:04

6、strptime(string, format)

将字符串时间转化为结构化时间

%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.

这里的字符串时间得和后面的结构化时间一一对应才行

import time
print(time.strptime("2018:06:09-15:21:36","%Y:%m:%d-%X"))
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
time.struct_time(tm_year=2018, tm_mon=6, tm_mday=9, tm_hour=15, tm_min=21, tm_sec=36, tm_wday=5, tm_yday=160, tm_isdst=-1)

7、asctime(p_tuple=None)可以加结构化参数，不加参数默认是当前时间

如果你没有自定义需求时间格式的话，可以之间用这个方法

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

import time
print(time.asctime())
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
Sat Jun  9 15:26:45 2018

8、ctime(seconds=None)可以加时间戳参数，不加参数默认是当前时间

跟7这个asctime出来的格式是一样的

print(time.ctime())#不加参数，默认是当前时间
 
Sat Jun  9 15:34:30 2018
 
print(time.ctime(1228629586.2798274))#加上时间戳（字符串时间）参数
 
Sun Dec  7 13:59:46 2008

9、datetime  这个相对来说跟好用，第一种用法比较精细，第二种格式也比较好看

import datetime
print(datetime.datetime.now())
print(datetime.datetime.now().strftime("%Y-%m-%d %X"))
 
C:\python35\python3.exe D:/pyproject/day21模块/time模块.py
 
2018-06-09 15:44:29.870926
 
2018-06-09 15:44:29