Python：从字符串中提取日期并放入列表

Question

I have a string like this:

   old_ActNacd_2016-12-21_07-09-08.txt:100:2016-12-21 07:08:20 - [HSM   ]Handle Identity Request. Send Identity Response. timeout: 1550s
   old_ActNacd_2016-12-21_08-21-04.txt:52:2016-12-21 07:21:42 - [HSM ]Handle Identity Request. Send Identity Response. timeout: 1550s
   old_ActNacd_2016-12-21_08-37-50.txt:49:2016-12-21 08:23:34 - [HSM ]Handle Identity Request. Send Identity Response. timeout: 1550s
   old_ActNacd_2016-12-21_15-00-47.txt:49:2016-12-21 08:39:16 - [HSM ]Handle Identity Request. Send Identity Response. timeout: 1550s

I tried doing like this:

  #creating list after taking the string out
  log_list = ostring.split('Handle Identity Request. Send Identity Response. timeout: 1550s')
    for itr in log_list:
        #getting the dates from the log_list
        match = re.search(r'\d{4}-\d{2}-\d{2}', itr)
        if match:
            date = datetime.strptime(match.group(), '%Y-%m-%d').date()

This process works fine, but i want to do only in one operation, rather than doing in two steps(splitting and matching)

  Note:-I want to create a list of dates from the string present between ":" and "space" in the string. I don't want the date present with "_ActNacd_" string.

So i will create a list which will contain dates:

['2016-12-21','2016-12-21', '2016-12-21', '2016-12-21']

Answer 1

With re.findall() , you can achieve that like below:

re.findall(r'(\d{4}\-\d{2}\-\d{2})', s)

If you want only the second date in each line, try:

re.findall(r':(\d{4}\-\d{2}\-\d{2})', s)

Output:

>>> import re
>>> 
>>> s = '''old_ActNacd_2016-12-21_07-09-08.txt:100:2016-12-21 07:08:20 - [HSM   ]Handle Identity Request. Send Identity Response. timeout: 1550s
... old_ActNacd_2016-12-21_08-21-04.txt:52:2016-12-21 07:21:42 - [HSM ]Handle Identity Request. Send Identity Response. timeout: 1550s'''
>>>
>>> re.findall(r':(\d{4}\-\d{2}\-\d{2})', s)
['2016-12-21', '2016-12-21']

Answer 2

尝试先按 \\n 分割，然后您可以逐行迭代并使用反向子字符串获取日期并使用 .append() 函数获取所需的列表