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Linq TakeWhile运算符

在LINQ中，只要指定的条件包含表达式，就使用TakeWhile运算符从数据源的列表/集合中获取元素。

LINQ TakeWhile运算符的语法

使用LINQ TakeWhile运算符的语法是根据指定的条件从列表中获取元素。

链接：https://www.learnfk.comhttps://www.learnfk.com/linq/linq-takewhile-partition-operator.html

来源：LearnFk无涯教程网

C#代码

IEnumerable<string> result = countries.TakeWhile(x => x.StartsWith("U"));

From the above syntax, we are getting the elements from the list where the elements starts with "U".

方法语法中的LINQ TakeWhile示例

下面是使用LINQ TakeWhile in方法语法从列表/集合获取元素的示例。

C#代码

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
//Array countries is created of string type.
            string[] countries = { "US", "UK", "Russia", "China", "Australia", "Argentina" };
/*TakeWhile operator is used which will print 
the values until the specified condition is satisfied.*/
            IEnumerable result = countries.TakeWhile(x => x.StartsWith("U"));
    //foreach loop will print the value of the result
            foreach (string s in  result) 
            {
                Console.WriteLine(s);
            }
                Console.ReadLine();
        }
    }
}

In the above example, we used TakeWhile () operator and a lambda expression in which we specified the condition which will select the countries that starts with "U." So, it returns only the first two elements.

输出：

查询语法中的LINQ TakeWhile示例

下面是在查询语法中使用LINQ TakeWhile运算符从列表中获取元素的示例。

using System;
using System. Collections;
using System.Collections.Generic;
using System. Linq;
using System. Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] countries = { "US", "UK", "China", "Russia", "Argentina", "India" };
//apply the query syntax to print the values upto the specified condition.StartWith("U").
            IEnumerable result = (from x in countries select x).TakeWhile(x => x.StartsWith("U"));
            foreach (string s in  result) 
            {
                Console.WriteLine(s);
            }
                Console.ReadLine();
        }
    }
}

输出：

执行上述程序后，我们会得到如下所示的输出：