LINQ (LINQ) Language Integrated Query 可以方便的查询并处理不同数据源的数据。PLINQ Parallel LINQ不光拥有LINQ的功能，还添加了并行操作的接口，以方便使用并提高效率。

更详细的信息： https://msdn.microsoft.com/zh-cn/library/dd460688(v=vs.110).aspx

一个简单的例子

用一个简单的例子足以说明PLINQ的使用。
简单的说明：
第一部分：先在一个文档中查询包含字母 “a”的单词首先使用 LINQ进行查询10000次，然后使用PLINQ进行同样的测试，看看效率有多少提高。 AsParallel() 是主要用到的接口。

第二部分：计算Short类型所有数字的和，同样测试两次使用LINQ和PLINQ。

第三部分：测试PLINQ的查找排序功能。使用的接口分别为AsOrdered()和orderby
AsOrdered：保持数据在数据源中的顺序不变。
orderby：按用户指定的顺序进行排序，升序/降序

示例程序：

using System; using System.Text; using System.Threading; using System.Threading.Tasks; using System.Diagnostics; using System.Linq; using System.IO; namespace Sample6_1_plink_basic { class Program { static int SumDefault(int[] array) { return array.Sum(); } static int SumAsParallel(int[] array) { return array.AsParallel().Sum(); } static string[] words = { "Day", "Car", "Land", "Road", "Sea", "Mountain", "River"}; static void Main(string[] args) { var customers = System.IO.File.ReadAllLines(@"D:\testdir\CSParallel_Program\Sample6-1 plink basic\target.txt"); int nCounter = 0; Console.WriteLine("============================================================"); Console.WriteLine("TEST NORMAL LINQ"); Console.WriteLine("============================================================"); var swatchpn = Stopwatch.StartNew(); for (int i = 0; i < 10000; i++) { var normalkeyLetters = from line in customers let keys = line.Split(‘ ‘) from key in keys where (key.Contains(‘a‘)) select key; var normalkeyList = normalkeyLetters.ToList(); nCounter = normalkeyList.Count(); } swatchpn.Stop(); Console.WriteLine("Word with letter a = {0}", nCounter); Console.WriteLine("LINQ Use Time: {0}", swatchpn.Elapsed); Console.WriteLine("\n\n"); Console.WriteLine("============================================================"); Console.WriteLine("TEST PARALLEL LINQ"); Console.WriteLine("============================================================"); nCounter = 0; var swatchp = Stopwatch.StartNew(); for (int i = 0; i < 10000; i++) { var keyLetters = from line in customers.AsParallel() let keys = line.Split(‘ ‘) from key in keys.AsParallel() where (key.Contains(‘a‘)) select key; var keyList = keyLetters.ToList(); nCounter = keyList.Count(); } swatchp.Stop(); Console.WriteLine("Word with letter a = {0}", nCounter); Console.WriteLine("PLINQ Use Time: {0}", swatchp.Elapsed); // Generate array. int[] array = Enumerable.Range(0, short.MaxValue).ToArray(); const int m = 10000; var s1 = Stopwatch.StartNew(); for (int i = 0; i < m; i++) { SumDefault(array); } s1.Stop(); var s2 = Stopwatch.StartNew(); for (int i = 0; i < m; i++) { SumAsParallel(array); } s2.Stop(); Console.WriteLine("\n\n"); Console.WriteLine("============================================================"); Console.WriteLine("CALCULATE SUMMARY TEST"); Console.WriteLine("============================================================"); Console.WriteLine("Default Summary: " + ((double)(s1.Elapsed.TotalMilliseconds * 1000000) / m).ToString("0.00 ns")); Console.WriteLine("Parallel Summary: " + ((double)(s2.Elapsed.TotalMilliseconds * 1000000) /m).ToString("0.00 ns")); Console.WriteLine("\n\n"); Console.WriteLine("============================================================"); Console.WriteLine("Parallel ASOrder Test"); Console.WriteLine("============================================================"); var orderwords = from word in words.AsParallel().AsOrdered() where (word.Contains(‘a‘)) select word; var orderletterList = orderwords.ToList(); for (int i = 0; i < orderletterList.Count; i++) { Console.WriteLine(orderletterList[i]); } Console.WriteLine("\n\n"); Console.WriteLine("============================================================"); Console.WriteLine("Parallel OrderBy Test"); Console.WriteLine("============================================================"); var orderbywords = from word in words.AsParallel() where (word.Contains(‘a‘)) orderby word ascending select word; var orderbyletterList = orderbywords.ToList(); for (int i = 0; i < orderbyletterList.Count; i++) { Console.WriteLine(orderbyletterList[i]); } Console.ReadKey(); } } }

测试结果：

测试其实运行过多次，关于单词的测试LINQ的结果在32至34秒，PLINQ大概在16至19秒，大约有50%的提升。

关于PLINQ中的数据分区