Question

我有一个字符串C＃列表，如下所示：

var list = new List<string>() { "A", "B", "C", "B", "C", "B", "D" };

我只想保留该列表中的唯一项目，以及多次删除的所有项目。

在这个例子中，它将是＆＃34; A＆＃34;和＆＃34; D＆＃34;在删除所有重复项之后离开。

Answer 1

这个怎么样：

var tmp = myList.GroupBy(x => x).Where(x => x.Count() == 1);

这将只返回那些恰好出现一次的条目。不返回具有重复项的条目。

现在简单地将该组列表压缩成如下：

var result = tmp.Select(x => x.Key).ToList();

Answer 2

list.GroupBy(x => x) //group the items together with themselves as the key
    .Where(g => g.Count() == 1) // select only those groups with only one element
    .Select(g => g.Key) // get the key out (.First() and .FirstOrDefault()
                        // would also work in this case, .Key tends to be a tiny bit faster).
    .ToList() // create a new list (if really necessary,
              // if you can skip this step do and things will be faster).

Answer 3

    var list = new List<string> { "A", "B", "C", "B", "C", "B", "D" };

    list = list.GroupBy(x => x).Where(g => g.Count() == 1).SelectMany(g => g).ToList();

您可以使用linq执行此操作。

Answer 4

     var list = new List<string> { "A", "B", "C", "B", "C", "B", "D" };
        var NewList = list.Except(list.GroupBy(i => i).Where(x=>x.Count()>1)
                                    .Select(ss => ss.FirstOrDefault()))
                                   .ToList();

Answer 5

List<string> list = new List<string>() { "A", "B", "C", "B", "C", "B", "D"};
    for (int i = 0; i < list.Count; i++)
        {
            string x = list.ElementAt(i);
            int count = 0;
            for (int j = 0; j < list.Count; j++)
            {
                if (list.ElementAt(j).Equals(x))
                {
                    count++;
                    if (count>1)
                    {
                        list.RemoveAll(y => y.Equals(x));
                        count = 0;
                    }
                }
            }
        }

试试这个...... 列表末尾只包含“A”“D”

只保留列表C＃中的唯一项

5 个答案: