Question

嗨！我有一个数据库模型，其中包含“ receivedMsg”，“ receivedTime”，“ SentBy”等信息

现在，我想将这些信息按数组排序。如果邮件未满24小时，则应采用今天数组；如果邮件已超过24小时，则应采用周数组。早于一周的所有内容都应位于更早数组中。

输出应以以下格式显示

row = soup.find('tr') # Extract and return first occurrence of tr
print(row)            # Print row with HTML formatting
print("=========Text Result==========")
print(row.get_text()) # Print row as text

请注意，我在C＃中使用linq

Answer 1

我希望，我了解你：

    public class RearrangeMessagesInArray
    {
        public void RearrangeMessagesInArrays(Message[] today, Message[] week, Message[] earlier)
        {
            // To work with linQ, convert array to list.
            var earlierAsList = earlier.ToList();
            // Add all messages to "earlier" - array, when its older then 7 days
            earlierAsList.ToList().AddRange(GetAllMessagesForGivenArrayAndTime(today, Times.Earlier));
            earlierAsList.ToList().AddRange(GetAllMessagesForGivenArrayAndTime(week, Times.Earlier));
            //return to "earlier" - array.
            earlier = earlierAsList.ToArray();

            // Add all messages to "week"-array, which is older than one day and newer than 7 days and remove all which is over 7 days
            week = GetAllMessagesForGivenArrayAndTime(week, Times.Week).ToArray();

            // Reassign "today"-array without messages, which are older than 1 one day.
            today = GetAllMessagesForGivenArrayAndTime(today, Times.Day).ToArray();

            PrintOutArrayAsJson(today, week, earlier);
        }

        private void PrintOutArrayAsJson(Message[] today, Message[] week, Message[] earlier)
        {
            today.ToList().ForEach(message => Console.WriteLine(WriteFromObject(message)));
            week.ToList().ForEach(message => Console.WriteLine(WriteFromObject(message)));
            earlier.ToList().ForEach(message => Console.WriteLine(WriteFromObject(message)));
        }

        private IEnumerable<Message> GetAllMessagesForGivenArrayAndTime(Message[] messages, Times time )
        {
            switch (time)
            {
                case Times.Day:
                    return from message in messages
                        where GetDaysDiffBetweenNowAndGivenDate(message.ReceivedTime) <= 1
                        select message;

                case Times.Week:
                    return from message in messages
                        where GetDaysDiffBetweenNowAndGivenDate(message.ReceivedTime) <= 7 
                              && GetDaysDiffBetweenNowAndGivenDate(message.ReceivedTime) > 1
                           select message;

                case Times.Earlier:
                    return from message in messages
                        where GetDaysDiffBetweenNowAndGivenDate(message.ReceivedTime) > 7
                        select message;
                default:
                    return null;

            }
        }

        private int GetDaysDiffBetweenNowAndGivenDate(DateTime givenDateTime)
        {
            return (DateTime.Today - givenDateTime).Days;
        }

        public class Message
        {
            public string ReceivedMessage { get; set; }
            public DateTime ReceivedTime { get; set; }
            public string SentBy { get; set; }
        }

        private enum Times { Day, Week, Earlier};

        // Create a User object and serialize it to a JSON stream.  
        public string WriteFromObject(Message message)
        {

            // Create a stream to serialize the object to.  
            var ms = new MemoryStream();

            // Serializer the User object to the stream.  
            var ser = new DataContractJsonSerializer(typeof(Message));
            ser.WriteObject(ms, message);
            byte[] json = ms.ToArray();
            ms.Close();
            return Encoding.UTF8.GetString(json, 0, json.Length);
        }

    }

Answer 2

您可以先定义范围，然后使用选择获得所需的结果。尚未真正检查这些范围是否正确，但是您应该对如何进行了解。参见dotnetfiddle example。

    var ranges = new List<GroupRange>
    {
        new GroupRange
        {
            Name = "Today",
            DateRange = (DateTime.Now.Date, DateTime.Now.AddDays(1).AddTicks(-1))
        },
        new GroupRange
        {
            Name = "This Week",
            DateRange = (DateTime.Now.FirstDayOfWeek(), DateTime.Now.LastDayOfWeek())
        },
        new GroupRange
        {
            Name = "Earlier",
            DateRange = (DateTime.MinValue, DateTime.Now.FirstDayOfWeek().AddDays(-1))
        },
    };

    var result = ranges
        .Select(r => new 
        { 
            Period = r.Name,
            Messages = data
                .Where(d => d.ReceivedTime >= r.DateRange.Item1 && 
                            d.ReceivedTime <= r.DateRange.Item2)
        });

Answer 3

难道不应该像这样复杂吗？

class Program
{
  static void Main( string[] args )
  {
    IEnumerable<Item> items = Enumerable.Empty<Item>();

    ( Age Age, Item[] Items )[] partitioned =
      items
      .Select( item => ComputeAge(item) )
      .GroupBy( x => x.Age )
      .Select( g => (
        Key    : g.Key ,
        Values : g.Select( x => x.Item )
                  .ToArray()
      ))
      .ToArray();
      ;

  }
  static ( Item Item, Age Age ) ComputeAge(Item item)
  {
    double days = (DateTime.Now - item.Received).TotalDays;
    Age age;

    // Does "week" means "with the last 7 days" or "within the current calendar week"
    // We'll assume it means within the last 7 days.
    if      ( days <  0.0 ) age = Age.Unknown;
    else if ( days <= 1.0 ) age = Age.Today;
    else if ( days <= 7.0 ) age = Age.Today;
    else                    age = Age.Earlier;

    return (item, age) ;
  }

}

public enum Age { Unknown = 0, Today = 1, ThisWeek = 2, Earlier = 3 }

class Item
{
  public string   Message  { get; set; }
  public string   Sender   { get; set; }
  public DateTime Received { get; set; }
}

如何从列表或任何数据库对象返回数据，按天，周或月分组

3 个答案: