推荐大家看看这篇文章：
http://qinxuye.me/article/details-about-time-module-in-python/
从时间戳到时间结构体：
time.localtime([secs])
从时间结构体转换到时间戳：
time.mktime(t)
从时间结构体打印出某个指定格式的字符串：
time.strftime(format[, t])
根据某个指定格式的字符串得到时间结构体：
time.strptime(string[, format])
format说明:
%a
- abbreviated weekday name
%A - full weekday name
%b - abbreviated month name
%B - full month name
%c - preferred date and time representation
%C - century number (the year divided by 100, range 00 to 99)
%d - day of the month (01 to 31)
%D - same as %m/%d/%y
%e - day of the month (1 to 31)
%g - like %G, but without the century
%G - 4-digit year corresponding to the ISO week number (see %V).
%h - same as %b
%H - hour, using a 24-hour clock (00 to 23)
%I - hour, using a 12-hour clock (01 to 12)
%j - day of the year (001 to 366)
%m - month (01 to 12)
%M - minute
%n - newline character
%p - either am or pm according to the given time value
%r - time in a.m. and p.m. notation
%R - time in 24 hour notation
%S - second
%t - tab character
%T - current time, equal to %H:%M:%S
%u - weekday as a number (1 to 7), Monday=1. Warning: In Sun Solaris Sunday=1
%U - week number of the current year, starting with the first Sunday as the first day of the first week
%V - The ISO 8601 week number of the current year (01 to 53), where week 1 is the first week that has at least 4 days in the current year, and with Monday
as the first day of the week
%W - week number of the current year, starting with the first Monday as the first day of the first week
%w - day of the week as a decimal, Sunday=0
%x - preferred date representation without the time
%X - preferred time representation without the date
%y - year without a century (range 00 to 99)
%Y - year including the century
%Z or %z - time zone or name or abbreviation
%% - a literal % character
例如打印当前时间:
time.strftime('%Y-%m-%d %H:%M:%S')