更改日期，正則表達式和python一個布赫

Question

我有以下格式

16th February 2011 
4th April 2009 
31st December 2007 

一串日期，我想將其更改爲這種格式

20110216 
20090404 
20071231 

我想這樣做在python中，我試過regex和time，但無法讓我的頭轉過來。

Answer 1

你不妨考慮parsedatetime zy日期匹配。

如果您的日期是從NN（序）月是一年的格式相當不變，這個工程：

dates="""\ 
16th February 2011 
4th April 2009 
31st December 2007""" 

import re 
import time 

for date in dates.splitlines(): 
    p=re.findall(r'(\d+)\w\w (\w+) (\d\d\d\d)',date) 
    d=time.strptime(' '.join(p[0]),'%d %B %Y') 
    iso=time.strftime('%Y%m%d',d) 
    print "{0:>20} =>{1:>30} =>{2:>15}".format(date,p,iso) 

打印：

16th February 2011 => [('16', 'February', '2011')] =>  20110216 
     4th April 2009 =>  [('4', 'April', '2009')] =>  20090404 
    31st December 2007 => [('31', 'December', '2007')] =>  20071231 

Answer 2

沒有進口，用於學習目的。

個月是一個月的字典。

months = {"January":"01","February":"02",...}  
# make sure all entries are strings, not integers 

for entry in entries: 
    # split by spaces. this is multiple assignment. 
    # the first split gets assigned to date, the second, to month, the third, to year. 
    day, month, year = entry.split() 

    # parse the date. the th/rd/nd part is always 2 characters. 
    date = day[:-2] 

    if len(date) == 1: 
     # make sure the date is two characters long 
     date = "0" + date 

    # concatenate 
    print year + months[month] + date 

Answer 3

做的兩個步驟：

1. 使用正則表達式(\d+)([a-z]{2})\s+([A-Za-z]+)\s+(\d{4})與空字符串

2. 使用time.strptime(string[, format])更換第二組轉換日期格式，你需要

Answer 4

您可以使用正則表達式來獲取信息，然後把它變成日期。

import datetime 
import re 
date_re = re.compile("^([0-9]+)[a-z]* (.+)$") 
example = "16th February 2011" 
m = date_re.match(example) 
dt = datetime.datetime.strptime("%s %s" % (m.group(1), m.group(2)), "%d %B %Y") 
print dt.strftime("%Y%m%d")