1507_reformat_date.py

'''
Given a date string in the form Day Month Year, where:
Day is in the set {"1st", "2nd", "3rd", "4th", ..., "30th", "31st"}.
Month is in the set {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}.
Year is in the range [1900, 2100].
Convert the date string to the format YYYY-MM-DD, where:

YYYY denotes the 4 digit year.
MM denotes the 2 digit month.
DD denotes the 2 digit day.

Example 1:
Input: date = "20th Oct 2052"
Output: "2052-10-20"
Example 2:

Input: date = "6th Jun 1933"
Output: "1933-06-06"
'''
class Solution:
    def reformDate(self, date):
        lst = date.split()
        month = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
        #dd
        dd = lst[0]
        if len(dd) < 4:
            dd = '0' + dd[:1]
        else:
            dd = dd[:2]

        #mm
        mm = str(month.index(lst[1]) + 1)
        if len(mm) < 2:
            mm = "0" + mm
        ##yy
        yy = lst[2]
        return yy + "-" + mm + "-" + dd