这是我的代码：public class Photos{ public long PhotoLabel { get; set; } public int UserID { get; set; }}List<Photos> photolist = new List<Photos>();var result1 = photolist.OrderByDescending(p => p.PhotoLabel).ThenBy(r => r.UserID).ToList();如果我现在显示内容，这就是我得到的（首先按降序排序，PhotoLabel然后按以下排序UserID：|------|---------------------|---------------------|| Row | UserID | PhotoLabel ||----------------------------|---------------------|| 1 | 92 | 20180729181046 ||----------------------------|---------------------|| 2 | 92 | 20180729181041 ||----------------------------|---------------------|| 3 | 92 | 20180729181037 ||----------------------------|---------------------|| 4 | 88 | 20180729174415 ||----------------------------|---------------------|| 5 | 88 | 20180729174405 ||----------------------------|---------------------|| 6 | 04 | 20180729174358 ||----------------------------|---------------------|| 7 | 1 | 20170924183847 ||----------------------------|---------------------|| 8 | 1 | 20170921231422 ||----------------------------|---------------------|| 9 | 1 | 20170920194624 ||----------------------------|---------------------|| 10 | 32 | 20170820114728 |从上面的排序表中，这就是我想要实现的：显示组 ofUserIDs和PhotoLabelswhereUserIDs在一个组中出现 3 次或更多次（例如：第 4 行和第 5UserID=88行where和第 6 行 whereUserID=04应该消除，因为它们UserID=88在组UserID=04中只出现两次，而在组中只出现一次）。仅显示最上面的组UserIDs并排除任何重复UserIDs（例如：第 7、8 和 9 行显示该UserID=1组。不要显示任何其他UserID=1组，例如第 14、15 和 16 行。）
3 回答
哈士奇WWW
TA贡献1799条经验 获得超6个赞
如果我没有误解要求，下面的功能可以正常工作（但它不应该是最有效的解决方案）
protected List<AnObject> aFunction(List<AnObject> sortedList)
{
//Display groups of UserIDs and PhotoLabels where UserIDs appear 3 or more times in one group (eg: rows 4 and 5 where UserID = 88 and row 6 where UserID = 04 should be eliminated since the UserID = 88 appears just twice in the group and UserID = 04 appears only once in the group).
//Display only the top most group of UserIDs and exclude any repeating UserIDs(eg: rows 7, 8 and 9 displays the UserID = 1 group.Don't display any other UserID=1 group such as rows 14,15 and 16.
int pivot = -1;
int cnt = 0;
List<AnObject> masterList = new List<AnObject>();
List<AnObject> subList = new List<AnObject>();
//List<int> Excluded = new List<int>();
foreach (AnObject r in sortedList)
{
if (pivot != r.UserID)
{
if (cnt > 2)
{
masterList.AddRange(subList);
//Excluded.Add(pivot);
}
subList.Clear();
pivot = -1;
cnt = 0;
//if (!Excluded.Contains(r.UserID))
if (!masterList.Any(x => x.UserID == r.UserID))
{
pivot = r.UserID;
}
}
subList.Add(r);
cnt++;
}
return masterList;
}
调用它进行测试
protected class AnObject
{
public AnObject(int uid, string photolabel)
{
this.UserID = uid;
this.PhotoLabel = photolabel;
}
public int UserID { get; set; }
public string PhotoLabel { get; set; }
}
protected void Execute()
{
List<AnObject> sortedList = new List<AnObject>();
sortedList.Add(new AnObject(92, "anystring"));
sortedList.Add(new AnObject(92, "anystring"));
sortedList.Add(new AnObject(92, "anystring"));
sortedList.Add(new AnObject(88, "anystring"));
sortedList.Add(new AnObject(88, "anystring"));
sortedList.Add(new AnObject(4, "anystring"));
sortedList.Add(new AnObject(1, "anystringfirst"));
sortedList.Add(new AnObject(1, "anystringfirst"));
sortedList.Add(new AnObject(1, "anystringfirst"));
sortedList.Add(new AnObject(32, "anystring"));
sortedList.Add(new AnObject(32, "anystring"));
sortedList.Add(new AnObject(32, "anystring"));
sortedList.Add(new AnObject(32, "anystring"));
sortedList.Add(new AnObject(1, "anystringafter"));
sortedList.Add(new AnObject(1, "anystringafter"));
sortedList.Add(new AnObject(1, "anystringafter"));
List<AnObject> bb = aFunction(sortedList);
}
扬帆大鱼
TA贡献1799条经验 获得超9个赞
请稍等！这不是最终答案！需要进一步修改！正在进行修改。
List<Photos> photolist = new List<Photos>()
{
new Photos() {UserID = 92, PhotoLabel = 20180729181046},
new Photos() {UserID = 92, PhotoLabel = 20180729181041},
new Photos() {UserID = 92, PhotoLabel = 20180729181037},
new Photos() {UserID = 88, PhotoLabel = 20180729174415},
new Photos() {UserID = 88, PhotoLabel = 20180729174405},
new Photos() {UserID = 04, PhotoLabel = 20180729174358},
new Photos() {UserID = 1, PhotoLabel = 20170924183847},
new Photos() {UserID = 1, PhotoLabel = 20170921231422},
new Photos() {UserID = 1, PhotoLabel = 20170920194624},
new Photos() {UserID = 32, PhotoLabel = 20170820114728},
new Photos() {UserID = 32, PhotoLabel = 20170820114725},
new Photos() {UserID = 32, PhotoLabel = 20170820114421},
new Photos() {UserID = 32, PhotoLabel = 20170820114416},
new Photos() {UserID = 1, PhotoLabel = 20170225151023},
new Photos() {UserID = 1, PhotoLabel = 20170225151000},
};
var photolist2 = photolist.GroupBy(g => g.UserID)
.Select(p => new
{
UserId = p.Key,
Count = p.Count()
})
.ToList();
var filteredPhotoList = photolist
.Join(photolist2,
photo => photo.UserID,
photo2 => photo2.UserId,
(photo, photo2) => new {UserId = photo.UserID, PhotoLabel =
photo.PhotoLabel, Count = photo2.Count})
.Where(p => p.Count > 2).Select(p => new
{
p.UserId, p.PhotoLabel
}).OrderByDescending(p => p.PhotoLabel).ThenBy(p => p.UserId).ToList();
喵喔喔
TA贡献1735条经验 获得超5个赞
SKLTFZ 和 TanvirArjel 的答案很接近，但没有达到预期的结果。我意识到你无法在 Linq 中实现上述所有内容，所以这就是我想出的，它实现了上面列出的所有内容：
PS：我将var result1重命名为ordered_photolist
List<Photos> ordered_photolist = photolist.OrderByDescending(p => p.PhotoLabel).ThenBy(r => r.UserID).ToList();
List<Photos> temp_photolist = new List<Photos>();
List<Photos> final_photolist = new List<Photos>();
int UserID = -1;
int UserIDCount = 0;
foreach (Photos p in ordered_photolist)
{
if (UserID == -1)
{
UserID = p.UserID;
temp_photolist.Add(p);
UserIDCount++;
}
else
{
if ( UserID == p.UserID )
{
temp_photolist.Add(p);
UserIDCount++;
}
else
{
if ( UserIDCount >= 3 )
{
// add temp_photolist to final list
int index = final_photolist.FindIndex(item => item.UserID == UserID);
if (index == -1)
{
// element does not exists, do what you need
final_photolist.AddRange(temp_photolist);
}
temp_photolist.Clear();
temp_photolist.Add(p);
UserIDCount = 1;
UserID = p.UserID;
}
else
{
temp_photolist.Clear();
UserIDCount = 0;
UserID = -1;
}
}
}
}
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