Python中的时间日期转换

import datetime

def reformat_subway_dates(date):

'''

The dates in our subway data are formatted in the format month-day-year.

The dates in our weather underground data are formatted year-month-day.

In order to join these two data sets together, we'll want the dates formatted

the same way.  Write a function that takes as its input a date in the MTA Subway

data format, and returns a date in the weather underground format.

Hint:

There are a couple of useful functions in the datetime library that will

help on this assignment, called strptime and strftime.

More info can be seen here and further in the documentation section:

http://docs.python.org/2/library/datetime.html#datetime.datetime.strptime

'''

date_formatted = datetime.datetime.strptime(date,'%m-%d-%y').strftime('%Y-%m-%d')# your code here

return date_formatted