python - 在Python中将所需的日期格式设置为文件名

Question

我想通过这种方式指定所需格式的日期作为文件名 ;

期间 [2019-10-01 09:00 ~ 2019-10-02 08:59:59] 将数据保存到191001-09.txt

我对此一无所知。我只能遵循简单的代码。 请让我知道如何修复它:

def timeStamped (fname, fmt = '19% m% d-% H {fname} '):
    return datetime.datetime.now (). strftime (fmt) .format (fname = fname)
with open (timeStamped ('. txt'), 'a') as f_last:
    f_last.write ('data')

Answer 1

Question: Conditional file name from datetime.now()

• 导入所需的对象
  • datetime
  • timedelta

  from datetime import datetime, timedelta
  

• 定义一个函数，从 datetime.date 对象获取所需的文件名:

  def fname_from_date(date):
      # Rule  09:00:00 ~ day + 1 08:59:59 
      midnight = date.replace(hour=0, minute=0, second=0)
      begin_of_day = date.replace(hour=9, minute=0, second=0)
      end_of_day = date.replace(hour=8, minute=59, second=59)
  
      # Are we between 'midnight' and 'end_of_day'
      if date >= midnight and date <= end_of_day:
          date = date - timedelta(days=1)
          print('\tNext day -1: {}'.format(date))
  
      # 191001-09.txt
      fname = date.strftime('%Y%m%d-09')
      return fname
  

• 使用静态日期测试函数 def fname_from_date(...。
  这需要从 datestr 创建一个 datetime.date 对象。

  for datestr in ['2019-10-01 09:00:00', 
                  '2019-10-01 11:01:11', 
                  '2019-10-02 07:07:07', 
                  '2019-10-02 08:59:59']:
      date = datetime.strptime(datestr, '%Y-%m-%d %H:%M:%S')
      print(date)
      fname = '{}.txt'.format(fname_from_date(date))
      print('\t{}'.format(fname))
  

  Output:

  2019-10-01 09:00:00
      20191001-09.txt
  2019-10-01 11:01:11
      20191001-09.txt
  2019-10-02 07:07:07
      Next day -1: 2019-10-01 07:07:07
      20191001-09.txt
  2019-10-02 08:59:59
      Next day -1: 2019-10-01 08:59:59
      20191001-09.txt
  

Usage:

fname = '{}.txt'.format(fname_from_date(datetime.now()))