LINQ查询

string[] names =
{
"Alonso", "zheng", "Smith", "Jones", "Smythe", "Small", "Ruiz", "Hsieh", "Jorgenson",
"Ilyich", "Singh", "Samba", "Fatimah"
};
var queryResults = from n in names
                   where n.StartsWith("S")
                   select n;
foreach (var item in queryResults)
{
Console.WriteLine(item);
}
Console.ReadKey();
}

string[] names =
{
"Alonso", "zheng", "Smith", "Jones", "Smythe", "Small", "Ruiz", "Hsieh", "Jorgenson",
"Ilyich", "Singh", "Samba", "Fatimah"
};
var queryResults = names.Where(n => n.StartsWith("s")); //以s开头
foreach (var item in queryResults)
{
Console.WriteLine(item);
}
Console.ReadKey();
}

orderby n

orderby n descending

orderby n.Substring(n.Length - 1);

names.orderby(n => n)；

Count()//计数 
Min(),
Max(),
Average()
Sum();

var queryResults = customers.Select(c => c.Region).Distinct(); 

var queryResults = from c in customers
                   orderby c.Region,c.COuntry,c.City
                   select new {c.ID,c.Region}

var queryResults = customers.OrderBy(c => c.Region)
                  .ThenBy(c => c.Country)
                  .ThenBy(c => c.City)
                  .select(c => new{c.ID,c.Region,c.Country})

foreach(var item in queryResults.Take(5)){ }

var queryResults = from c in customers
join o in orders on c.ID equals o.ID
select new{c.ID,c.City,}

XDocument xdoc = new XDocument(
new XElement("customers",
new XElement("customers",
new XAttribute("ID", "A"),
new XAttribute("City", "New York"),
new XAttribute("Region", "North America"),
new XElement("order",
new XAttribute("Item", "Tire")
)
),
new XElement("customer")
)
);

XDocument xdoc = XDocument.Parse(@"<customers>.....</customers>")