查询数组－－传统方式、匿名方法和lambda表达式比较

最新推荐文章于 2024-01-10 20:54:35 发布

最新推荐文章于 2024-01-10 20:54:35 发布 · 138 阅读

文章标签：

#Linq #.net

本文通过传统方法、匿名方法、改进匿名方法及lambda表达式四种方式演示了如何在C#中查找整数数组中的偶数。每种方法都提供了具体的实现细节，并通过实例展示了如何筛选出数组中的偶数。

要求：使用传统方式（。net 1.1 类库）、匿名方法和lambda表达式查找一个int数组中的偶数。

using System;

using System.Collections;

using System.Linq;

using System.Text;

using System.Collections.Generic;

using System.Runtime.Serialization;



namespace TestCS

{

    class Program

    {



        public static void Main(string[] args)

        {

            Console.WriteLine("Tranditional");

            TranditionalDelegateSyntax();

            Console.WriteLine("AnonymousMethod");

            AnonymousMethodSyntax();

            Console.WriteLine("AdvancedAnonymousMethodSyntax");

            AdvancedAnonymousMethodSyntax();

            Console.WriteLine("LambdaExpressionSyntax");

            LambdaExpressionSyntax();



            

        }

        

        static void LambdaExpressionSyntax()

        {

            List<int> list = new List<int>();

            list.AddRange(new int[] { 2, 4, 3, 28, 45, 9 });



            //no "predicate" ,no "delegate",no other stand-alone method

            //ArgumentsToProcess => StatementsToProcessThem

            //List<int> evenNumbers =list.FindAll(i=>(i%2)==0);

            //也可以

            //List<int> evenNumbers = list.FindAll((int i) => (i % 2) == 0);

            //也可以

            //List<int> evenNumbers = list.FindAll((i) => (i % 2) == 0);

            //也可以

            //List<int> evenNumbers = list.FindAll((i) => ((i % 2) == 0));

            //也可以

            List<int> evenNumbers =list.FindAll((i)=>

                {

                    bool isEven=((i%2)==0);

                    return isEven;

                });



            foreach (int en in evenNumbers)

            {

                Console.WriteLine(en.ToString());

            }

        }





        static void AdvancedAnonymousMethodSyntax()

        {

            List<int> list = new List<int>();

            list.AddRange(new int[] { 2, 4, 3, 28, 45, 9 });



            //no 'predicate',no other stand-alone method

            List<int> evenNumbers = list.FindAll(

                delegate(int i)

                {

                    return (i % 2) == 0;

                }

                );





            foreach (int en in evenNumbers)

            {

                Console.WriteLine(en.ToString());

            }

        }



        static void AnonymousMethodSyntax()

        {

            List<int> list = new List<int>();

            list.AddRange(new int[] { 2, 4, 3, 28, 45, 9 });



            //no other stand-alone method

            List<int> evenNumbers = list.FindAll(new Predicate<int>(delegate(int i)

                {

                    return (i % 2) == 0;

                }

            ));



            

            foreach (int en in evenNumbers)

            {

                Console.WriteLine(en.ToString());

            }

        }







        private static void TranditionalDelegateSyntax()

        {

            List<int> list = new List<int>();

            list.AddRange(new int[] { 2,4,3,28,45,9});





            

            Predicate<int> callback = new Predicate<int>(IsEvenNumber);

            List<int> evenNumbers = list.FindAll(callback);



            foreach (int en in evenNumbers)

            {

                Console.WriteLine(en.ToString());

            }

        }



        static bool IsEvenNumber(int i)

        {

            return (i % 2) == 0;

        }



       

        



       

    }

}