多条件排序(C# and Lua)
C#
| 升序排序 | OrderBy | 按升序对序列的元素进行排序 | 
| ThenBy | 按升序对序列中的元素执行后续排序 | |
| 降序排序 | OrderByDescending | 按降序对序列的元素排序 | 
| ThenByDescending | 按降序对序列中的元素执行后续排序 | 
public class Fruit
{
    public int id;
    public string name;
    public float price;
    public float weight;
}
List<Fruit> list = new List<Fruit>();
list.Add(new Fruit { id = 2, name = "苹果", price = 9.9f ,weight = 500});
list.Add(new Fruit { id = 5, name = "西瓜", price = 1.2f, weight = 5000 });
list.Add(new Fruit { id = 1, name = "草莓", price = 29.9f, weight = 80 });
list.Add(new Fruit { id = 3, name = "香蕉", price = 6f, weight = 800 });
list.Add(new Fruit { id = 4, name = "哈密瓜", price = 2.5f, weight = 3000 });
升序排序
IOrderedEnumerable<Fruit> result = list.OrderBy(x => x.id)
    .ThenBy(x=>x.price)
    .ThenBy(x=>x.weight);
降序排序
IOrderedEnumerable<Fruit> result = list.OrderByDescending(x => x.id)
    .ThenByDescending(x=>x.price)
    .ThenByDescending(x=>x.weight);

Lua
local list = {
  [1] = {id = 101,name = "小明",age = 16,score = 88};
  [2] = {id = 103,name = "小红",age = 15,score = 91};
  [3] = {id = 107,name = "小刚",age = 16,score = 81};
  [4] = {id = 105,name = "小丽",age = 15,score = 91};
  [5] = {id = 104,name = "小龙",age = 14,score = 88};
}
table.sort(list,function(a,b)
    if a.score == b.score then
      if a.age == b.age then
        return a.id > b.id
      else
        return a.age > b.age
      end  
    else
      return a.score > b.score
    end  
  end)
