下面是HashSet<string>方法:

public static string[] RemoveDuplicates(string[] s)
{
    HashSet<string> set = new HashSet<string>(s);
    string[] result = new string[set.Count];
    set.CopyTo(result);
    return result;
}

不幸的是，这个解决方案也需要。net框架3.5或更高版本，因为HashSet直到该版本才被添加。你也可以使用array.Distinct()，这是LINQ的一个特性。

你可以在使用数组列表时使用这段代码

ArrayList arrayList;
//Add some Members :)
arrayList.Add("ali");
arrayList.Add("hadi");
arrayList.Add("ali");

//Remove duplicates from array
  for (int i = 0; i < arrayList.Count; i++)
    {
       for (int j = i + 1; j < arrayList.Count ; j++)
           if (arrayList[i].ToString() == arrayList[j].ToString())
                 arrayList.Remove(arrayList[j]);

  private static string[] distinct(string[] inputArray)
        {
            bool alreadyExists;
            string[] outputArray = new string[] {};

            for (int i = 0; i < inputArray.Length; i++)
            {
                alreadyExists = false;
                for (int j = 0; j < outputArray.Length; j++)
                {
                    if (inputArray[i] == outputArray[j])
                        alreadyExists = true;
                }
                        if (alreadyExists==false)
                        {
                            Array.Resize<string>(ref outputArray, outputArray.Length + 1);
                            outputArray[outputArray.Length-1] = inputArray[i];
                        }
            }
            return outputArray;
        }

在下面找到答案。

class Program
{
    static void Main(string[] args)
    {
        var nums = new int[] { 1, 4, 3, 3, 3, 5, 5, 7, 7, 7, 7, 9, 9, 9 };
        var result = removeDuplicates(nums);
        foreach (var item in result)
        {
            Console.WriteLine(item);
        }
    }
    static int[] removeDuplicates(int[] nums)
    {
        nums = nums.ToList().OrderBy(c => c).ToArray();
        int j = 1;
        int i = 0;
        int stop = 0;
        while (j < nums.Length)
        {
            if (nums[i] != nums[j])
            {
                nums[i + 1] = nums[j];
                stop = i + 2;
                i++;
            }
            j++;
        }
        nums = nums.Take(stop).ToArray();
        return nums;
    }
}

这是基于我刚刚解决的一个测试的一点贡献，可能对这里其他顶级贡献者的改进有所帮助。 以下是我所做的事情:

I used OrderBy which allows me order or sort the items from smallest to the highest using LINQ I then convert it to back to an array and then re-assign it back to the primary datasource So i then initialize j which is my right hand side of the array to be 1 and i which is my left hand side of the array to be 0, i also initialize where i would i to stop to be 0. I used a while loop to increment through the array by going from one position to the other left to right, for each increment the stop position is the current value of i + 2 which i will use later to truncate the duplicates from the array. I then increment by moving from left to right from the if statement and from right to right outside of the if statement until i iterate through the entire values of the array. I then pick from the first element to the stop position which becomes the last i index plus 2. that way i am able to remove all the duplicate items from the int array. which is then reassigned.

泛型扩展方法:

public static IEnumerable<TSource> Distinct<TSource>(this IEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
{
    if (source == null)
        throw new ArgumentNullException(nameof(source));

    HashSet<TSource> set = new HashSet<TSource>(comparer);
    foreach (TSource item in source)
    {
        if (set.Add(item))
        {
            yield return item;
        }
    }
}

下面是HashSet<string>方法:

public static string[] RemoveDuplicates(string[] s)
{
    HashSet<string> set = new HashSet<string>(s);
    string[] result = new string[set.Count];
    set.CopyTo(result);
    return result;
}

不幸的是，这个解决方案也需要。net框架3.5或更高版本，因为HashSet直到该版本才被添加。你也可以使用array.Distinct()，这是LINQ的一个特性。