C＃通用列表

C＃通用列表 - 如何随机为每个项目分配“等级”？(C# Generic List - How to Randomly Assign a “Rank” To Each Item?)

所以我有以下通用列表：

var topTenSomething = new List<Something>();

这是件事：

public class Something { public string Name { get; set; } public int Rank { get; set; } }

所以我想随机分配“Rank”属性，但需要从集合中的1个项目中进行排序。

因此，如果集合有3个项目，我想随机分配从1到3的排名：

一些名字 其他一些名字 还有别的

然后下一次，它可能是：

其他一些名字 一些名字 还有别的

明白我的意思了吗？

不知道怎么做 - 任何想法？

这是一个简单的研发原型 - 所以不要担心性能/为什么我这样做。 （真实的将具有由数据库分配的等级）

对LINQ /非LINQ版本感到满意 - 只要它有效。

So i have the following generic list:

var topTenSomething = new List<Something>();

Here is Something:

public class Something { public string Name { get; set; } public int Rank { get; set; } }

So i want to randomly assign the "Rank" property, but it needs to be ordered from 1-number of items in the collection.

So if the collection has 3 items, i want to randomly assign ranks from 1 to 3:

Some Name Some Other Name Something Else

Then next time, it could be:

Some Other Name Some Name Something Else

Know what i mean?

Not sure how to do it - any ideas?

This is for a simple R&D prototype - so don't worry about performance/why i am doing this. (the real one will have rank assigned by database)

Happy with either a LINQ/non-LINQ version - as long as it works.

最满意答案

喜欢这个：

var rand = new Random(); var sequence = Enumerable.Range(0, list.Count).OrderBy(i => rand.Next()).ToList(); for(var i = 0; i < list.Count; i++) list[i].Rank = sequence[i];

如果您希望列表按随机排名排序：

var rand = new Random(); list.Sort((a, b) => rand.Next(-1, 2)); //Exclusive upper bound for(var i = 0; i < list.Count; i++) list[i].Rank = i;

但是，这不是有效的排序（ a < b并不意味着b > a ）并且可能导致意外结果。

Like this:

var rand = new Random(); var sequence = Enumerable.Range(0, list.Count).OrderBy(i => rand.Next()).ToList(); for(var i = 0; i < list.Count; i++) list[i].Rank = sequence[i];

If you want the list to be sorted by the random rank:

var rand = new Random(); list.Sort((a, b) => rand.Next(-1, 2)); //Exclusive upper bound for(var i = 0; i < list.Count; i++) list[i].Rank = i;

However, this is not a valid ordering (a < b does not imply b > a) and may cause unexpected results.

C＃通用列表 - 如何随机为每个项目分配“等级”？(C# Generic List - How to Randomly Assign a “Rank” To Each Item?)

所以我有以下通用列表：

var topTenSomething = new List<Something>();

这是件事：

public class Something { public string Name { get; set; } public int Rank { get; set; } }

所以我想随机分配“Rank”属性，但需要从集合中的1个项目中进行排序。

因此，如果集合有3个项目，我想随机分配从1到3的排名：

一些名字 其他一些名字 还有别的

然后下一次，它可能是：

其他一些名字 一些名字 还有别的

明白我的意思了吗？

不知道怎么做 - 任何想法？

这是一个简单的研发原型 - 所以不要担心性能/为什么我这样做。 （真实的将具有由数据库分配的等级）

对LINQ /非LINQ版本感到满意 - 只要它有效。

So i have the following generic list:

var topTenSomething = new List<Something>();

Here is Something:

public class Something { public string Name { get; set; } public int Rank { get; set; } }

So i want to randomly assign the "Rank" property, but it needs to be ordered from 1-number of items in the collection.

So if the collection has 3 items, i want to randomly assign ranks from 1 to 3:

Some Name Some Other Name Something Else

Then next time, it could be:

Some Other Name Some Name Something Else

Know what i mean?

Not sure how to do it - any ideas?

This is for a simple R&D prototype - so don't worry about performance/why i am doing this. (the real one will have rank assigned by database)

Happy with either a LINQ/non-LINQ version - as long as it works.

最满意答案

喜欢这个：

var rand = new Random(); var sequence = Enumerable.Range(0, list.Count).OrderBy(i => rand.Next()).ToList(); for(var i = 0; i < list.Count; i++) list[i].Rank = sequence[i];

如果您希望列表按随机排名排序：

var rand = new Random(); list.Sort((a, b) => rand.Next(-1, 2)); //Exclusive upper bound for(var i = 0; i < list.Count; i++) list[i].Rank = i;

但是，这不是有效的排序（ a < b并不意味着b > a ）并且可能导致意外结果。

Like this:

var rand = new Random(); var sequence = Enumerable.Range(0, list.Count).OrderBy(i => rand.Next()).ToList(); for(var i = 0; i < list.Count; i++) list[i].Rank = sequence[i];

If you want the list to be sorted by the random rank:

var rand = new Random(); list.Sort((a, b) => rand.Next(-1, 2)); //Exclusive upper bound for(var i = 0; i < list.Count; i++) list[i].Rank = i;

However, this is not a valid ordering (a < b does not imply b > a) and may cause unexpected results.