IList<Model> query = (from item in list where ("," + projectmodel.ids + ",").Contains("," + item.id + ",") select item).ToList<Model>(); 回到顶部 Select(取list中的id列数据,并按逗号分隔成字符串。例:1,2,3,4,5) //方式一 //分成key-value的数组 string[] id = list.Select...
}//var item2=list.OrderBy(x=>Guid.NewGuid());//随机排序方法一Random rand=newRandom();//随机排序方法二varitem2 = list.OrderBy(x =>rand.Next());foreach(Employee employeeinitem2) { Console.WriteLine(employee); } Console.WriteLine("---");varitem3 = list.OrderBy(x => x.Name[x....
C# LINQ LINQ(Language Integrated Query,语言集成查询)。在C# 语言中集成了查询语法,可以用相同的语法访问不同的数据源。 命名空间System
var(isMatch,match)="337845818@qq.com".MatchEmail();// 可在appsetting.json中添加EmailDomainWhiteList和EmailDomainBlockList配置邮箱域名黑白名单,逗号分隔,如"EmailDomainBlockList": "^\\w{1,5}@qq.com,^\\w{1,5}@163.com,^\\w{1,5}@gmail.com,^\\w{1,5}@outlook.com",boolisInetAddress=...
sale.Date =DateTime.Now.AddDays(random.Next(-30, 30)); sales.Add(sale); }returnsales; } } 2.投影 Select查询 public static voidSelectDemo() {List<Product> products =Product.GetProducts(5);//查询商品本身varquery = products.Select(p => p);foreach(variteminquery) ...
The following code fills the list using the Range method, then calls the Enumerable.OrderBy method with a simple lambda expression to arrange the sequence in random order:VB 複製 ' From RangeDemo in the sample: Dim rnd As New System.Random Dim items = Enumerable.Range(1, 10) D...
(You don't have to use "bk"; I just chose that name at random. It's a variable, so give it any name you wish.) This variable provides a way to identify objects and object members from the source data within the query. Since Library is a collection, it wouldn't make sense to ...
ToString(new Random().Next(100000, int.MaxValue));//生成随机字符串 27.权重随机筛选功能 var data=new List<WeightedItem<string>>() { new WeightedItem<string>("A", 1), new WeightedItem<string>("B", 3), new WeightedItem<string>("C", 4), new WeightedItem<string>("D", 4), }; ...
The sample procedure in Figure 7 creates a generic List(Of Integer) containing random integers. It then takes values while each item is less than a specific number and displays the results (the GetCommaList method in the sample creates a comma-delimited string containing the conte...
//quary取值⽅法,此处可写可不写ToList()。//经过测试，数据30W，⽆ToList()⽐ToList()的耗时少⼏百毫秒，具体原因未知。下⾯是实验的⼏组数据：第⼀次9689 9398，第⼆次13529 10458，第三次10772 10392，第四次11370 10833。实际差距并不⼤。foreach (var item in quary.ToList()){ //...