C#中linq

class IntroToLINQ
{        
    static void Main()
    {
        // The Three Parts of a LINQ Query: 
        //  1. Data source. 
        int[] numbers = new int[7] { 0, 1, 2, 3, 4, 5, 6 };

        // 2. Query creation. 
        // numQuery is an IEnumerable<int> 
        var numQuery =
            from num in numbers
            where (num % 2) == 0
            select num;

        // 3. Query execution. 
        foreach (int num in numQuery)
        {
            Console.Write("{0,1} ", num);
        }
    }
}

Northwnd db = new Northwnd(@"c:\northwnd.mdf");

// Query for customers in London.
IQueryable<Customer> custQuery =
    from cust in db.Customers
    where cust.City == "London"
    select cust;

List<int> numQuery2 =
    (from num in numbers
     where (num % 2) == 0
     select num).ToList();

// or like this: 
// numQuery3 is still an int[] 

var numQuery3 =
    (from num in numbers
     where (num % 2) == 0
     select num).ToArray();

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