public void PrintPersonsInCity(string city)
{
var personsInCity = (from person in persons
where person.Address == city
orderby person.FirstName
select person);
var x = personsInCity.AsQueryable();
Console.WriteLine("\nOriginal person list\n====================");
foreach (var person in x)
{
PrintPerson(person);
}
// Add a new person to the persons list
var p = new Person { FirstName = "Ron", LastName = "Miller",
Address = "Washington" };
persons.Add(p);
Console.WriteLine("\nChanged person list\n===================");
foreach (var person in x)
{
PrintPerson(person);
}
// Hmm...what type is personsInCity and in which namespace is it?
// TODO: Print the type and namespace of personsInCity
Console.WriteLine("\npersonsInCity namespace\n===================");
Console.WriteLine(x.GetType());
}
/// <summary>
/// 诞生的理由-以一种统一的方式操作各种数据源，减少数据访问的复杂性
/// 1、数据访问对象类型 XML,OBJECT,SQL 后续还有LINQ TO ENTITY
/// 2、var 类似Javascript里面弱类型的变量
/// 3、感觉类似用SQL脚本式语言操作其他数据类型，
/// 提供了对象领域和数据领域之间对接的土壤
///
/// 强类型和弱类型语言的区别
/// 1、变量的使用要有严格的定义，所有变量必须先使用后定义
/// （不同类型的变量不可以放在同一块存储区域）
/// 2、弱类型的语言，数据类型是可以被忽略的语言，一个变量可以可以赋值不同数据类型的值
/// （不同类型的变量可以放在同一块存储区域）给予了开发人员滥用的机会
/// 但是只有在运行时才会发现
/// 3、c#也不是‘绝对’的强类型的语言
/// object是属于弱类型 var变量代码智能的体现 可以根据上下文推断出类型
/// 4、弱类型语言有VBScirpt PHP
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
//MethodInfo[] methods = typeof(string).GetMethods();
////m-隐式声明的变量
//var result = from m in methods
// where m.IsStatic != true
// select m.Name;
//var resultDis = (from m in methods
// where m.IsStatic != true
// select m.Name).Distinct();
////System.Linq.Lookup`2+Grouping[System.String,System.Reflection.MethodInfo]
//var resultDis1 = from m in methods
// where m.IsStatic != true
// group m by m.Name;
////into 对象赋值 匿名参数 将对象属性赋值给NEW 之后的新变量
////select cl1,count(1) from a group by a.cl1
////NEW { } 匿名类(不用写类的声明，直接实例化)
////名字可以不用写 大括号里的为类初始化器 省去了构造函数 NEW的同时 给对象属性赋值
////var 懒人专用
//var resultDis2 = from m in methods
// where m.IsStatic != true
// group m by m.Name into g
// select new { MethodName = g.Key, OverLoad = g.Count() }; //Myclass my = new Myclass();
//foreach (var item in resultDis2)
//{
// Console.WriteLine(item.ToString());
//}
////一、LINQ
////1、DLINQ LinqtoSql 基于关系的.NET语言集成查询以对象形式管理关系数据，并提供了丰富的查询功能
////2、LINQ TO XML
////3、LINQ TO OBJECT
////4、LINQ TO DATASET
////5、LINQ TO ENTITIES
//var age = 16;
//var username = "******";
//var userlist = new[] { "a", "b", "c" };
//foreach (var user in userlist)
//{
// Console.WriteLine(user);
//}
////匿名类型
////允许开发人员自定义行内类型，无需显示定义类型 实现了对象的转换和投影
//var date = new { username = "******", age = "16" };
//Console.WriteLine("username:{0} age:{1}", date.username, date.age);
////lambda表达式
////和2.0产生内联的方法是一致的
//var list = new[] { "aaa", "ab", "cc" };
////参数列表=》表达式或者语句块
////参数：多个参数 一个参数 或者无参数
////表达式：相当于函数体
//var lamdaResult = Array.FindAll(list, s => (s.IndexOf("a") > -1));
//foreach (var a in lamdaResult)
//{
// Console.WriteLine(a);
//}
//是否包含负值
//string strReg_3 = @"^-?[0-9]+\.*[0-9]*$";
//Regex regex_3 = new Regex(strReg_3, RegexOptions.IgnoreCase);
//string a = "-34.00";
//if (regex_3.IsMatch(a))
//{
// MatchCollection match = regex_3.Matches(a);
// Console.Write(Convert.ToDecimal(match[0].ToString()));
//}
//string a = "_^尿视黄醇结合蛋白$";
//string[] b = a.Split('_');
//for (int i = 0; i < b.Length; i++)
//{
// Console.WriteLine(b[i]);
//}
////skip skipwhile take takewhile
//string[] names = { "DebugLZQ", "DebugMan", "Sarah", "Jerry", "Tom", "Linda", "M&M", "Jeffery" };
////1.Take用于从一个序列的开头返回指定数量的元素
////
////a.在数组上直接使用Take方法
//foreach (string name in names.Take(3))
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("-----");
////b.在LINQ返回的IEnumerable<T>序列上使用Take方法
//var query = from string name in names
// where name.Length <= 3
// select name;
//foreach (string name in query.Take(1))
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("----------------------------");
//Console.ReadKey(false);
////2.TakeWhile 用于获取指定序列从头开始符合条件的元素，直到遇到不符合条件的元素为止
////
//var takenames = names.TakeWhile(n => n.Length > 4);
//var takenames2 = names.TakeWhile((n, i) => n.Length < 10 && i < 3);
//foreach (string name in takenames)
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("-----");
//foreach (string name in takenames2)
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("----------------------------");
//Console.ReadKey(false);
////3.Skip跳过序列中指定数量的元素
////
//foreach (string name in names.Skip(5))
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("-----");
//var query_skip = (from name in names
// where name.Length >= 3
// select name).Skip(2);
//foreach (string name in query_skip.Skip(2))
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("----------------------------");
//Console.ReadKey(false);
////4.SkipWhile 用于跳过序列总满足条件的元素，然会返回剩下的元素
////跳过名字长度大于3的
//var takenames_SkipWhile = names.SkipWhile(n => n.Length > 3);
//foreach (string name in takenames_SkipWhile)
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("-----");
//var takenames_SkipWhile2 = names.SkipWhile((n, i) => n.Length > 3 && i > 2);
//foreach (string name in takenames_SkipWhile2)
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("----------------------------");
//Console.ReadKey(false);
////小结Take、Skip获得第N到第M个元素
//var names_TakeAndSkip = names.Skip(5).Take(3);
//var names_TakeAndSkip2 = (from name in names
// select name).Skip(5).Take(3);
//foreach (string name in names_TakeAndSkip)
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("-----");
//foreach (string name in names_TakeAndSkip2)
//{
// Console.Write("{0} ", name);
//}
//Console.WriteLine();
//Console.WriteLine("----------------------------");
//Console.ReadKey(false);
#region OTHER
//int[] myarr = new int[] { 1, 2, 3 };
////Console.WriteLine("{0}", mianji());
////Console.WriteLine("{0}", mianji(2.0));
//string a = "1.42×10^4";
//string tar = "细菌数";
//string b = "<50qefasfasfsafsfsd0";
//string c = "细菌数：250-300个/油镜";
//Regex rege = new Regex(@"×10\^");
//string B = Regex.Replace(a, @"×10\^", "E");
//string aac = "3.4E-05";
//Regex rege1 = new Regex(@"[0-9]+\.*[0-9]*");
//Console.WriteLine(ChangeDataToD(aac));
//Console.WriteLine(b.Contains(""));
//Console.WriteLine(a.Substring(2));
//Console.WriteLine(CutYuJuZhiJianHuo(c, "G+球菌", "88", false));
//Console.WriteLine(c.Substring(c.IndexOf(tar) + tar.Length));
//MatchCollection matchCol = rege1.Matches(c);
//for (int i = 0; i < matchCol.Count; i++)
//{
// Console.WriteLine(matchCol[i].ToString());
//}
//List<string> matchStr = new List<string>();
//string regeBiaoben = string.Empty;
//string regeItemName = string.Empty;
//string regeCulResult = string.Empty;
//string regeAntiName = string.Empty;
//regeBiaoben = ".*";
//regeItemName = "药敏定量试验";
//regeCulResult = ".*";
//regeAntiName = ".*";
//matchStr.Add(regeBiaoben);
//matchStr.Add(regeItemName);
//matchStr.Add(regeCulResult);
//matchStr.Add(regeAntiName);
//for (int i = 0; i < matchStr.Count; i++)
//{
// Console.WriteLine(matchStr[i].ToString());
//}
//matchStr[2] = "hhhh";
//for (int i = 0; i < matchStr.Count; i++)
//{
// Console.WriteLine(matchStr[i].ToString());
//}
////DateTime datatime1 = "";
////DateTime datatime2 = "";
////TimeSpan ts = DateTime1.Subtract(DateTime2).Duration();
////day = ts.Days.ToString();
//DateTime dt = Convert.ToDateTime("2017-08-09 00:00:00");
//DateTime dt1 = Convert.ToDateTime("2017-08-10 13:00:00");
//Console.WriteLine(dt.Date);
//Console.WriteLine((dt.Date - dt1.Date).Days.ToString());
//Console.WriteLine(dt.Subtract(dt1).Duration());
//Person p = new Person();
//p.name = "5";
//p.age = 12;
//p.score = 12.02m;
//Person p1 = new Person();
//p1.name = "2";
//p1.age = 13;
//p1.score = 12.00m;
//Person p2 = new Person();
//p2.name = "4";
//p2.age = 14;
//p2.score = 12.02m;
//Person p3 = new Person();
//p3.name = "3";
//p3.age = 15;
//p3.score = 12.00m;
//List<Person> lstP = new List<Person>();
//lstP.Add(p);
//lstP.Add(p1);
//lstP.Add(p2);
//lstP.Add(p3);
//lstP = lstP.OrderBy(d => d.score).ThenBy(d => d.name).ToList();
//Console.WriteLine("---------------");
//foreach (Person item in lstP)
//{
// Console.WriteLine(item.name + '-' + item.score);
//}
//string pattern = @"(\d{3})-(\d{3}-\d{4})";
//string input = "212-555-6666 906-932-1111 415-222-3333 425-888-9999";
//MatchCollection matches = Regex.Matches(input, pattern);
//foreach (Match match2 in matches)
//{
// Console.WriteLine("Area Code: {0}", match2.Groups[1].Value);
// Console.WriteLine("Telephone number: {0}", match2.Groups[2].Value);
// Console.WriteLine();
//}
//(?!=,).*(?=h)
//string testStr = ",hhh111.00,adsfasdfs,asdf";
//string strReg_3 = @"(,.*a.*)";
//Regex regex_3 = new Regex(strReg_3, RegexOptions.IgnoreCase);
//MatchCollection match = regex_3.Matches(testStr);
//string[] matchs=regex_3.Split(testStr);
//string a = Guid.NewGuid().ToString();
//Console.WriteLine(a);
//Console.WriteLine(match[0]);
//Console.WriteLine("Current Processor:" + System.Environment.ProcessorCount);
//string aa = "<180.00";
//decimal result = 0.0m;
//Console.WriteLine(decimal.TryParse(aa.ToString(), out result) ? result : 0);
//string bb = "DR_02_20031".Replace("|", "','") + "|";
//Console.WriteLine(bb.Substring(0, bb.Length - 1));
//string s1 = "，最远的标点，asdfhasohz中欧第一个奥的斯嘎哈送服哀悼啊但是看第二个了附件啊师傅，奥萨蒂放假哦阿三第二个奥i的司法，asdfhasohz中欧奥的斯嘎哈送服哀悼啊但是看了附件啊师傅，奥萨蒂放假哦阿三奥i的司法";
//List<string> s = CutContentHQHList("我", "，|。|；", "，|。|；", s1, RegexOptions.IgnoreCase);
//Console.WriteLine(aa.Contains(".*"));
//string s2 = "-2.0";
//string S3 = "78×10^5";
//Console.WriteLine(decimal.TryParse(s2, out result) ? result : 0);
//Console.WriteLine(S3.Contains(@"×10^"));
//Console.WriteLine(DateTime.Now.TimeOfDay);
//Console.WriteLine(System.Environment.ProcessorCount);
#endregion
#region 编码
//字符集-一个字符和数字对应的表 表示每一个字符都对应一个数字 其实就是一张表
//编码格式-这些字符对应的数字如何在计算机中存储
//ASCII GB2312 GB18030-简体 BIG5-繁体
//ASCII 最早的字符集 一个字符用一个字节表示 不过它只能表示部分字符
//Mbcs多字节表示->Unicode 一个字符两个字节
//UCS2-一个字符两个字节 UCS4-一个字符用4个字节
//UTF7(汉字4字节 英文1个字节 目前主要用于邮件方面) UTF8（汉字3个字节 英文1个字节）
//UTF16 UTF32 都是以Unicode都是以为基础进行编码的
//Unicode和BigEndianUnicode都是用2个字节对一个字符进行编码格式;只不过它们储存字符的顺序正好相反*/
//string msg = "测试CESHI";
//string msg1 = "C";//63 //99 //67
//string receive = string.Empty;
//List<byte> lst = new List<byte>();
//lst.AddRange(Encoding.ASCII.GetBytes(msg1));
//lst.AddRange(ASCIIEncoding.ASCII.GetBytes(msg));
//lst.AddRange(UTF8Encoding.ASCII.GetBytes(msg));
//lst.AddRange(UnicodeEncoding.ASCII.GetBytes(msg));
//lst.AddRange(UTF32Encoding.ASCII.GetBytes(msg));
//lst.AddRange(UTF7Encoding.ASCII.GetBytes(msg));
//string str2 = Encoding.ASCII.GetString(lst.ToArray());
//receive = BitConverter.ToString(lst.ToArray());
//lst = new List<byte>(Encoding.UTF7.GetBytes(msg));
//receive = BitConverter.ToString(lst.ToArray());
//lst = new List<byte>(Encoding.UTF8.GetBytes(msg));
//receive = Encoding.UTF8.GetString(lst.ToArray());
//receive = BitConverter.ToString(lst.ToArray());
//byte[] length = BitConverter.GetBytes(0x7D02);
//Console.WriteLine(str2);
//Console.WriteLine(receive);
//SELECT SELECTMANY
//string[] text = { "Albert was here", "Burke slept late", "Connor is happy" };
//var tokens = text.Select(s => s.Split(' '));
//var tokenss = text.SelectMany(s => s.Split(' '));
//foreach (string[] line in tokens)
// foreach (string token in line)
// Console.Write("{0} ", token);
//Console.WriteLine();
//foreach (string token in tokenss)
// Console.Write("{0} ", token);
//Switch 不加Case 报错
//string s = "123";
//switch (s)
//{
// case "123":
// Console.WriteLine("111");
// //break;
// case "234":
// Console.WriteLine("222");
// break;
// default:
// break;
//}
//闭包
List<Person> lstp = new List<Person>()
{
new Person {name="a",age=14,score=20 },
new Person {name="b",age=14,score=20 },
new Person {name="c",age=14,score=20 }
};
for (int i = 0; i < 3; i++)
{
Person p = lstp[i];
ThreadPool.QueueUserWorkItem((obj) =>
{
Thread.Sleep(1000);
//闭包的陷阱 索引超出范围 内部变量引用外部函数的最终值
//Person p = lstp[i];
Console.WriteLine(p.name);
});
}
#endregion
Console.ReadLine();
}
private static void PrintPerson(Person person)
{
Console.WriteLine(person.FirstName + " " + person.LastName +
" - " + person.Address);
}