c#集合去重排序常用方法

 list与数组转Hashset&SortedSet

//创建hashset去重
var hashSet = new HashSet(){1,1,2,2};
Console.WriteLine("HashSet:"+String.Join(", ", hashSet));
// HashSet:1, 2//创建list包含重复元素
var ints = new List{1,1,3,3,2,2};
//创建数组转HashSe包含重复元素
int[] numbers = { 1, 1, 3, 2, 2 };//list转HashSet
var set = ints.ToHashSet();
Console.WriteLine("List转HashSet:"+String.Join(", ", set));
//List转HashSet:1, 3, 2var immutableSortedSet = ints.ToImmutableSortedSet();
Console.WriteLine("immutableSortedSet:"+String.Join(", ", immutableSortedSet));//数组转HashSet
var hashSet1 = new HashSet(numbers);
Console.WriteLine("数组转HashSet:"+String.Join(", ", hashSet1));
//数组转HashSet:1, 3, 2//数组转SortedSet
var sortedSet = new SortedSet(numbers);
Console.WriteLine("数组转SortedSet:"+String.Join(", ", sortedSet));
//数组转SortedSet:1, 2, 3

当hashset存的是类时

创建饮料类

public class Drink
{public String Name { get; set; }public int Price { get; set; }
}

new一个HashSet存放饮料类 

var drinks = new HashSet();
drinks.Add(new Drink{Name = "牛奶",Price = 19});
drinks.Add(new Drink{Name = "牛奶",Price = 20});
drinks.Add(new Drink{Name = "茉莉花茶",Price = 19});
drinks.Add(new Drink{Name = "茉莉花茶",Price = 19});
foreach (var drink in drinks)
{Console.WriteLine(drink.Name+drink.Price);
}

 打印出来并未去重

自定义比较规则

public class DrinkEquelityCompare : IEqualityComparer
{public bool Equals(Drink x, Drink y){//Name相等去除return x.Name == y.Name;}public int GetHashCode(Drink obj){return base.GetHashCode();}
}

重新new一个类

//var drinks = new HashSet(new DrinkEquelityCompare());
drinks.Add(new Drink{Name = "牛奶",Price = 19});
drinks.Add(new Drink{Name = "牛奶",Price = 20});
drinks.Add(new Drink{Name = "茉莉花茶",Price = 19});
drinks.Add(new Drink{Name = "茉莉花茶",Price = 19});
foreach (var drink in drinks)
{Console.WriteLine(drink.Name+drink.Price);
}

此时打印以及去除掉Name相同的值了

 SortedSet存放类时自定义排序规则

 还是用刚刚的Drink类

public class DrinkCompare : IComparer
{public int Compare(Drink x, Drink y){//返回值>0 x大；  返回值=0，一样大；  返回值小于0，y大return x.Price-y.Price;}
}

添加数据

SortedSet sorted = new(new DrinkCompare());
sorted.Add(new Drink{Name = "橘汁",Price = 19});
sorted.Add(new Drink{Name = "牛奶",Price = 20});
sorted.Add(new Drink{Name = "茉莉花茶",Price = 17});
sorted.Add(new Drink{Name = "可乐",Price = 21});foreach (var drink in sorted)
{Console.WriteLine(drink.Name+drink.Price);
}

打印出来的数据以及按照price进行排序了 

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