在Django的学习过程中的时间处理过程中遇到了strftime函数，于是结合《python cookbook》和python docs 对time模块中常用的一些操作和函数做了一点总结和归纳。
- time.time()
代表了从特定时间点，也被称作纪元（epoch：[英] [?i:p?k] [美] [??p?k, ?i?pɑk] ）开始所经历的秒数，是一个看起来不够直观的浮点数，这个时间根据不同的平台有所不同，一般为1970年1月1日午夜。例：
>>> import time
>>> time.time()
1299080804.953
>>>print time.asctime(time.gmtime(0))
Thu Jan 0100:00:001970
- time.gmtime([secs]), time.localtime([secs])
time.gmtime将任何时间戳（参数secs所代表的秒数）转化为一个元组，该元组为GMT（格林威治标准时），亦即UTC（世界标准时间）。也可以传递一个时间戳（从纪元开始经历的秒数）给time.localtime，会根据当前时区进行时间转化。
>>> time.gmtime(0)
time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)
>>> time.localtime(0)
time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=8, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)
- time.asctime([t])
将struct_time转换为一个由24字符组成的字符串（24-character string），格式如：
Thu Mar 0300:16:042011
- time.strftime(format[, t])
将一个元组（tuple）或者struct_time类，即参数t，转换为指定格式的字符串
- time.striptime(string[, format])
跟time.strftime相反的操作，解析给定的字符串并返回一个struct_time类。例：
>>> from time import strftime, gmtime
>>> strftime("%a %d %b %Y %H:%M:%S")
‘Thu 03 Mar 2011 00:29:41‘
>>> strftime("%a %d %b %Y %H:%M:%S", gmtime())
‘Wed 02 Mar 2011 16:30:09‘
>>> time.strptime("30 Feb 11", "%d %b %y")
...
ValueError: day is out of range for month
>>> time.strptime("28 Feb 11", "%d %b %y")
time.struct_time(tm_year=2011, tm_mon=2, tm_mday=28, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=59, tm_isdst=-1)
- time.sleep(secs)
可以实现在python程序中的延时，单位为秒，并支持浮点数非整数秒的延时。例：
>>>for i in range(3):
time.sleep(2.5)
print"hello world!"
hello world!
hello world!
hello world!
>>>
附一：struct_time
| Index | Attribute | Values |
|---|---|---|
| 0 | tm_year | (for example, 1993) |
| 1 | tm_mon | range [1, 12] |
| 2 | tm_mday | range [1, 31] |
| 3 | tm_hour | range [0, 23] |
| 4 | tm_min | range [0, 59] |
| 5 | tm_sec | range [0, 61]; see (1) in strftime()description |
| 6 | tm_wday | range [0, 6], Monday is 0 |
| 7 | tm_yday | range [1, 366] |
| 8 | tm_isdst | 0, 1 or -1; see below |
附二：directives can be embedded in the format string
| Directive | Meaning | Notes |
|---|---|---|
| %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. | |
| %d | Day of the month as a decimal number [01,31]. | |
| %H | Hour (24-hour clock) as a decimal number [00,23]. | |
| %I | Hour (12-hour clock) as a decimal number [01,12]. | |
| %j | Day of the year as a decimal number [001,366]. | |
| %m | Month as a decimal number [01,12]. | |
| %M | Minute as a decimal number [00,59]. | |
| %p | Locale’s equivalent of either AM or PM. | (1) |
| %S | Second as a decimal number [00,61]. | (2) |
| %U | Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0. | (3) |
| %w | Weekday as a decimal number [0(Sunday),6]. | |
| %W | Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0. | (3) |
| %x | Locale’s appropriate date representation. | |
| %X | Locale’s appropriate time representation. | |
| %y | Year without century as a decimal number [00,99]. | |
| %Y | Year with century as a decimal number. | |
| %Z | Time zone name (no characters if no time zone exists). | |
| %% | A literal ‘%‘ character. |
参考：1. python cookbook
2. docs：http://docs.python.org/library/time.html#time.struct_time