Python日期格式化常用的一些格式化占位符

%a Abbreviated weekday name
%A Full weekday name
%b Abbreviated month name
%B Full month name
%c Date and time representation appropriate for locale
%d Day of month as decimal number (01 - 31)
%H Hour in 24-hour format (00 - 23)
%I Hour in 12-hour format (01 - 12)
%j Day of year as decimal number (001 - 366)
%m Month as decimal number (01 - 12)
%M Minute as decimal number (00 - 59)
%p Current locale's A.M./P.M. indicator for 12-hour clock
%S Second as decimal number (00 - 59)
%U Week of year as decimal number, with Sunday as first day of week (00 - 51)
%w Weekday as decimal number (0 - 6; Sunday is 0)
%W Week of year as decimal number, with Monday as first day of week (00 - 51)
%x Date representation for current locale
%X Time representation for current locale
%y Year without century, as decimal number (00 - 99)
%Y Year with century, as decimal number
%% Percent sign
%f Millisecond

注：Python不支持%z, %Z等时区的格式占位符

字符串->日期格式

from datetime import datetime

tString = '1990-7-18-23-11-20'
format = '%Y-%m-%d-%H-%M-%S'
t = datetime.strptime(tString, format)

日期格式->字符串

from datetime import datetime

t = datetime.now()
format = '%Y-%m-%d-%H-%M-%S'
tString = t.strftime(format)