python的时间处理-time模块

time模块

时间的表示方法有三种：

• 时间戳：表示的是从1970年1月1日0点至今的秒数
• 格式化字符串表示：这种表示更习惯我们通常的读法，如2018-04-24 00:00:00
• 格式化元祖表示：是一个具有九个元素的元祖

时间戳与格式元组的互相转换

import time   #导入time模块

d = time.time()  # 显示当前的时间戳

d
Out[16]: 1524570062.944023

time.localtime(d)    #把时间戳转换为含9个元素的元组，转换为当地时间
Out[17]: time.struct_time(tm_year=2018, tm_mon=4, tm_mday=24, tm_hour=19, tm_min=41, tm_sec=2, tm_wday=1, tm_yday=114, tm_isdst=0)

time.gmtime(d)     #把时间戳转换为含9个元素的元组，转换为UTC时间
Out[18]: time.struct_time(tm_year=2018, tm_mon=4, tm_mday=24, tm_hour=11, tm_min=41, tm_sec=2, tm_wday=1, tm_yday=114, tm_isdst=0)

ld = time.localtime(d)  #

ld.tm_year    #转换的元组，可以根据需要单独计算对应的时间
Out[20]: 2018

time.mktime(ld)  # 把元组在转换回时间戳
Out[21]: 1524570062.0

备注：UTC时间为格林威治时间，比东八区晚8个小时！

时间戳与格式化字符串的转换：

时间戳-------->格式化元组---------->格式化字符串

help(time.strftime)
Help on built-in function strftime in module time:

strftime(...)
    strftime(format[, tuple]) -> string   #函数的格式使用
    
    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.

ld   #格式化元组的数据
Out[22]: time.struct_time(tm_year=2018, tm_mon=4, tm_mday=24, tm_hour=19, tm_min=41, tm_sec=2, tm_wday=1, tm_yday=114, tm_isdst=0)

time.strftime("%Y-%m-%d %H:%M:%S", ld)
Out[25]: '2018-04-24 19:41:02'

time.strftime("%Y-%m-%d %X", ld)
Out[26]: '2018-04-24 19:41:02'

time.strftime("%Y-%m-%d %X %p", ld) #时间戳转换为格式化元组
Out[27]: '2018-04-24 19:41:02 PM'

#字符串转换为格式化元组，注意格式对应
time.strptime('2018-04-24 19:41:02 PM',"%Y-%m-%d %H:%M:%S %p")
Out[32]: time.struct_time(tm_year=2018, tm_mon=4, tm_mday=24, tm_hour=19, tm_min=41, tm_sec=2, tm_wday=1, tm_yday=114, tm_isdst=-1)

根据时间戳转换为字符格式

help(time.ctime)
Help on built-in function ctime in module time:

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.


time.ctime(time.time())
Out[34]: 'Tue Apr 24 20:02:46 2018'

根据struct_time格式的元组转换为字符串

help(time.asctime)
Help on built-in function asctime in module time:

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.


time.asctime(ld)
Out[36]: 'Tue Apr 24 19:41:02 2018'

datetime模块

dateimte模块对time模块进行了封装，提供了更多功能的接口：

在csdn上看到一个博客，讲的蛮详细的，博主禁止转载，因此附上链接。datetime模块