C# 如何从嵌套的C列表中删除重复值

我的模型设置如下所示：

public class ReportScheduleModel
{
    public string Day { get; set; }
    public List<ReportTimes> reportTimes { get; set; }
}

public class ReportTimes
{
    public byte hourOfDay { get; set; }
    public byte minuteOfDay { get; set; }
    public string reportType { get; set; }
}

重要信息：请确保ReportTimes类以合理的方式实现GetHashCode和Equals：即，相同的条目总是散列到相同的值，不同的时间条目散列到不同的值

然后，您可以为每天创建一个HashSet数据结构，并线性遍历嵌套列表，将所有列表中的所有报告时间按天添加到相应的集合中

以上内容将确保每天只保留唯一的ReportTimes实例。在ReportTimes实例的数量上，它将具有线性时间性能

当然，您也可以重复使用哈希集，一次只做一天

var sets  = new Dictionary<string, HashSet<ReportTimes>>();

// assuming ReportSchedule is the list of ReportScheduleModel items
foreach(var scheduleItem in ReportSchedule)
{
     if(!sets.ContainsKey(scheduleItem.Day))
        sets.Add(scheduleItem.Day, new HashSet<ReportTimes>());

     foreach(var rt in scheduleItem.reportTimes)
     {
          sets[scheduleItem.Day].Add(rt);
     }
}

// at this point, each set in the sets dictionary will contain only unique items
// if you wanted to get all the unique report times for Sunday you would use something like:
foreach(var rt in sets["Sunday"])
{
    Console.WriteLine("{0}:{1} - {2}", rt.hourOfDay, rt.minuteOfDay, rt.reportType);
}

我希望上面的例子足够清楚。正如我在开始时所说的，请确保在ReportTime类中实现GetHashCode和Equals。下面是一个例子：

public class ReportTimes
{
    public byte hourOfDay { get; set; }
    public byte minuteOfDay { get; set; }
    public string reportType { get; set; }

    public override int GetHashCode()
    {            
        return reportType.GetHashCode ^ (hourOfDay << 8) ^ (minuteOfDay);
    }

    public override bool Equals(object other)
    {
        if(other is ReportTimes)
        {
            var ort = (ReportTimes)other;

            // returns true if the 'other' object represents the same time & type
            return    ort.hourOfDay.Equals(hourOfDay);
                   && ort.minuteOfDay.Equals(minuteOfDay);
                   && ort.reportType.Equals(reportType);
        }

        return false;  // if comparing to a non-ReportTimes object always return false
    }
}

---

我建议使用。我以前从未使用过哈希集，是否可以从我上面提供的信息中快速创建一个示例，或者创建一个与我的数据类似的链接。请参阅编辑；请务必阅读有关哈希集的内容！除非您了解它的作用以及为什么有用，否则无法有效地使用它。哈希集类似于字典，在字典中，键和值之间没有区别。它们的行为很像数学集合。多次添加项目只会添加一次，不会产生错误。

var sets  = new Dictionary<string, HashSet<ReportTimes>>();

// assuming ReportSchedule is the list of ReportScheduleModel items
foreach(var scheduleItem in ReportSchedule)
{
     if(!sets.ContainsKey(scheduleItem.Day))
        sets.Add(scheduleItem.Day, new HashSet<ReportTimes>());

     foreach(var rt in scheduleItem.reportTimes)
     {
          sets[scheduleItem.Day].Add(rt);
     }
}

// at this point, each set in the sets dictionary will contain only unique items
// if you wanted to get all the unique report times for Sunday you would use something like:
foreach(var rt in sets["Sunday"])
{
    Console.WriteLine("{0}:{1} - {2}", rt.hourOfDay, rt.minuteOfDay, rt.reportType);
}

public class ReportTimes
{
    public byte hourOfDay { get; set; }
    public byte minuteOfDay { get; set; }
    public string reportType { get; set; }

    public override int GetHashCode()
    {            
        return reportType.GetHashCode ^ (hourOfDay << 8) ^ (minuteOfDay);
    }

    public override bool Equals(object other)
    {
        if(other is ReportTimes)
        {
            var ort = (ReportTimes)other;

            // returns true if the 'other' object represents the same time & type
            return    ort.hourOfDay.Equals(hourOfDay);
                   && ort.minuteOfDay.Equals(minuteOfDay);
                   && ort.reportType.Equals(reportType);
        }

        return false;  // if comparing to a non-ReportTimes object always return false
    }
}