class Program

    {

        static void Main( string[ ] args )

        {

            SumEx1( );

        }

        class package

        {

            public string Company { get; set; }

            public double weight { get; set; }

        }

        public static void SumEx1( )

        {

            List<package> pack = new List<package>

            { new package {Company = "aaa",weight=11.00},

              new package {Company = "bbb",weight=22.00},

              new package { Company = "Wingtip Toys", weight = 33.00 },

              new package { Company = "Adventure Works", weight = 44.00 } };

            //string.Sum()方法，合计数字类型总和。

            double totalWeight = pack.Sum( p => p.weight );

            Console.WriteLine( totalWeight);

            // Contains() 方法，是否在子字符串里出现过，为true,则只显示此字符串。

            IEnumerable<package> var = from num in pack where num.Company.Contains("aaa") select num;

            foreach ( package item in var )

            {

                Console.WriteLine( item.Company);

                Console.WriteLine( item.weight );

            }

        }

    }

namespace Console_linq2

{

    class Program

    {

        struct MyStruct

        {

            public string name;

            public int age;

            private string p;

            public MyStruct( string p )

            {

                this.p = "a";

                name = "张三";

                age = 21;

            }

        }

        static void Main( string[ ] args )

        {

            stringQueryFunction( );

            IntQueryFunction( );

            LinqToSqlFunction( );

            StructFunction( );

            ArrayReverse( );

            ListReverse( );

            ToListFunction( );

        }

        private static void ToListFunction( )

        {

            //int[ ] age = new int[ ] { 34, 54, 76, 57, 54, 6, 3, 53 };

            string[ ] fruits = { "apple", "passionfruit", "banana", "mango",

                      "orange", "blueberry", "grape", "strawberry" };

            Console.WriteLine( "ToList()之前：" );

            foreach ( string item in fruits )

            {

                Console.WriteLine( item);

            }

            Console.WriteLine( "ToList()之后aaaa：" );

            

            //ToList()方法，位数组的每个元素计算个数

            List<int> lengths = fruits.Select( fruit => fruit.Length ).ToList( );

            foreach ( int item in lengths )

            {

                Console.WriteLine( item);

            }

            Console.WriteLine( );

        }

        private static void ListReverse( )

        {

            Console.WriteLine( "LastOrDefault( )的使用：" );

            //LastOrDefault( ) 返回列表中的最后一个元素

            string[ ] fruits = { "aa", "bb", "cc", "dd" };

            string last = fruits.LastOrDefault( );

            Console.WriteLine(

                String.IsNullOrEmpty( last ) ? "<string is null or empty>" : last );

            /*

             This code produces the following output:

             <string is null or empty>

            */

            Console.WriteLine( "List<int>泛型倒序：");

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

            list.Add( 23 );

            list.Add( 4 );

            list.Add( 34 );

            list.Add( 8 );

            list.Add( 3 );

            list.Add( 5 );

            list.IndexOf( 34 );

           

            Console.WriteLine( "排序之前：");

            for ( int i = 0; i < list.Count; i++ )

            {

                Console.WriteLine( list[i]);

            }

            list.Sort( );

            Console.WriteLine( "排序之后：");

            foreach ( int item in list )

            {

                Console.WriteLine( item );

            }

            Console.WriteLine( );

            Console.WriteLine( "倒序之后：");

           

            list.Reverse( );

            foreach ( int item in list )

            {

                Console.WriteLine( item);

            }

        }

        private static void ArrayReverse( )

        {

            int[ ] inta = { 34, 6, 58, 53, 6 };

            Console.WriteLine( "给inta[]排序");

            for ( int i = 0; i < inta.Length; i++ )

            {

                for ( int j = 0; j < inta.Length-i-1; j++ )

                {

                    if ( inta[j] < inta[j+1] )

                    {

                        int tmp = inta[ j + 1 ];

                        inta[ j + 1 ] = inta[ j ];

                        inta[ j ] = tmp;

                    }

                }

                Console.WriteLine( inta[i]);

            }

        }

        private static void StructFunction( )

        {

            MyStruct m = new MyStruct( );

            string[] message = { "aaa", "ddd" };

            

            Console.WriteLine( " IEnumerable<MyStruct>:" );

            IEnumerable<MyStruct> query = from c in message where c != null orderby c select new MyStruct

                ( m.name = c.ToString() );

            foreach ( var item in query )

            {

                Console.WriteLine( item.age+"\t"+ item.name );

           

            }

        }

        private static void LinqToSqlFunction( )

        {

            

            List<double> quantity = new List<double> { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

            List<double> quantity1 = new List<double> { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

            List<string> str = new List<string> { "a", "c", "d", "e", "f", "g", "h" };

            List<string> str1 = new List<string> { "a", "c", "d", "e", "f", "g", "h" };

            var query = from q in quantity

                        select q;

            Console.WriteLine( "Avg:" );

            Console.WriteLine( query.Average( ) );

            Console.WriteLine( "count:" );

            Console.WriteLine( query.LongCount( ) );//计算元素总量

            Console.WriteLine( "int64count" );

            Console.WriteLine( query.Count( ) );//计算元素总量

            Console.WriteLine( "Max:" );

            Console.WriteLine( query.Max( ) );//计算元素最大值

            Console.WriteLine( "Min:" );

            Console.WriteLine( query.Min( ) );//计算元素最小值

            Console.WriteLine( "sum:" );

            Console.WriteLine( query.Sum( ) );//计算元素总和

            double average = quantity.Average( );//计算平均值

            Console.WriteLine( "avg:" );

            Console.WriteLine( average );

            IEnumerable<double> avl = quantity.Distinct( );

            Console.WriteLine( "List:" );

            foreach ( double item in avl )

            {

                Console.WriteLine( item );

            }

            Console.WriteLine( );

            Console.WriteLine( "将两个集合通过 Union 方法联合之后显示,Union方法只显示不重复的数据：" );

            var inion2 = str.Union( str1 );

            foreach ( var item in inion2 )

            {

                Console.Write(item+" " );

            }

            Console.WriteLine( );

            IEnumerable<double> union = quantity.Union( quantity1 );

            foreach ( double item in union )

            {

                Console.Write( item + " " );

            }

            Console.WriteLine( );

            Console.WriteLine( "Intersect【出现多少个重复】:" );

            IEnumerable<double> Intersects = quantity.Intersect( quantity1 );

            foreach ( double item in Intersects )

            {

                Console.Write( item+" " );

            }

            Console.WriteLine( );

            Console.WriteLine( "Except【出现多少个不重复】:" );

            IEnumerable<double> Excepts = quantity.Except( quantity1 );

            foreach ( double item in Excepts )

            {

                Console.Write( item + " " );

            }

            Console.WriteLine( );

            Console.WriteLine( "Range方法的使用：3,表示从数字3开始，10，表示10个数字" );

            var coolmath1 = Enumerable.Range( 3, 10 ).Reverse( );

            foreach ( int item in coolmath1 )

            {

                Console.Write( item+" " );

            }

            Console.WriteLine( );

            Console.WriteLine( "Select( x => x * 5 ) x表示集合中的每一个数字：" );

            var coolmath = Enumerable.Range( 3, 10 ).Select( x => x * 5 );

            foreach ( int item in coolmath )

            {

                Console.Write( item+" " );

            }

        }

        private static void stringQueryFunction( )

        {

            string[ ] name = { "赵丽蓉", "马季", "侯耀文", "马三立", "侯宝林", "乔布斯" };

            //模糊查询

            //IEnumerable<string> val = from num in name where num.StartsWith( "马" ) select num;

            //排序

            IEnumerable<string> val = from num in name orderby num select num;

            var mum = (from m in name select m).First();

            Console.WriteLine( "var First()返回指定的条件:" );

            foreach ( var item in mum )

            {

                Console.WriteLine( item);

            }

            Console.WriteLine( "+++++++++++++++++");

            foreach ( var item in val )

            {

                Console.WriteLine( item );

            }

        }

        private static void IntQueryFunction( )

        {

            int[ ] age = new int[ ] { 5, 6, 78, 45, 4, 768, 899, 67, 5, 900 };

            var numQuery = from num in age where num > 800 && num <= 900 select num;

            IEnumerable<int> query = ( from c in age orderby c select c ).Take( 4 );

            Console.WriteLine( "Take( 4 )指定出现4个" );

            foreach ( var item in query )

            {

                Console.WriteLine( item);

            }

            Console.WriteLine("=============================");

            Console.WriteLine( );

            Console.WriteLine( "age where num > 800 && num <= 900的有： " );

            foreach ( var item in numQuery )

            {

                Console.Write( "{0} ", item );

            }

            Console.WriteLine( );

        }

    }

}