言語セット クエリ Ganmge hteg.ratedQuw の LINQ は、C# プログラミング言語のクエリ構文を統合しており、同じ構文を使用して異なるデータ ソースにアクセスできます。 LINQ はさまざまなデータ ソースに抽象化レイヤーを提供するため、同じ構文を使用できます。
フィルター演算子は、要素を返すための条件を定義します。
フィルター演算子 | 説明 |
---|---|
where | 述語を使用し、ブール値を返します |
OfTypeb54c2c292509147c0b54128f4eb90887 | 型に基づいて要素をフィルターします |
応用例:
使用例:
var racers = from r in Formulal.Racers where r.Wins > 15 && r.Country == "Brazil" select r;
OfType932180d09744fbdf0a8e29ec0e372585
还是上面的例子
IEnumerable<MyIntClass> ienuList = from r in intList1 where r.Integar > 3 select r; //返回默认的IEnumerable集合 List<MyIntClass> ienuList2 = (from r in intList1 where r.Integar > 3 select r).ToList(); //返回List MyIntClass[] ienuList2 = (from r in intList1 where r.Integar > 3 select r).ToArray();//返回数组 var dict = (from r in intList1 where r.Integar > 3 select r).ToDictionary(r=>r.Name,r=>r.Integar); //字典,key是name, value:Integar IEnumerable<MyIntClass> ienuList2 = (from r in intList1 where r.Integar > 3 select r).AsEnumerable();
这些生成操作符返回 一 个新集合
Generation operators | 描述 |
---|---|
Empty | 集合是空的 |
Range | 返回一系列数字 |
Repeat | 返回始终重复一个值的集合 |
IEnumerable<int> ints = Enumerable.Range(3, 10); //{3,4,5,6,7,8,9,10,11,12}IEnumerable<int> emptyInts = Enumerable.Empty<int>(); //生成一个空集合IEnumerable<int> ints2= Enumerable.Repeat(6,8);//生成8个6的集合
//选手实体类 public class Racer { public Racer(string firstName = null, string lastName = null, string country = null, int starts = 0,int wins = 0, IEnumerable<int> years = null, IEnumerable<string> cars = null) { this.FirstName = firstName; this.LastName = lastName; this.Country = country; this.Starts = starts; this.Wins = wins; var yearList = new List<int>(); if (years != null) { foreach (var year in years) { yearList.Add(year); } this.Years = yearList.ToArray(); } if (cars != null) { var carList = new List<string>(); foreach (var car in cars) { carList.Add(car); } this.Cars = carList.ToArray(); } public string FirstName { get; set; } public string LastName { get; set; } //赢得比赛的次数 public int Wins { get; set; } //所属国家 public string Country { get; set; } //开始做的年龄 public int Starts { get; set; } //车型数组 public string[] Cars { get; private set; } //赢得冠军的年份 public int[] Years { get; private set; } } }
//选手List public static List<Racer> Racers = new List<Racer>(40) { new Racer("Nino", "Farina", "Italy", 33, 5, new int[] { 1950 }, new string[] { "Alfa Romeo" }), new Racer("Alberto", "Ascari", "Italy", 32, 10, new int[] { 1952, 1953 }, new string[] { "Ferrari" }), new Racer("Juan Manuel", "Fangio", "Argentina", 51, 24, new int[] { 1951, 1954, 1955, 1956, 1957 }, new string[] { "Alfa Romeo", "Maserati", "Mercedes", "Ferrari" }), new Racer("Mike", "Hawthorn", "UK", 45, 3, new int[] { 1958 }, new string[] { "Ferrari" }), new Racer("Phil", "Hill", "USA", 48, 3, new int[] { 1961 }, new string[] { "Ferrari" }), new Racer("John", "Surtees", "UK", 111, 6, new int[] { 1964 }, new string[] { "Ferrari" }), new Racer("Jim", "Clark", "UK", 72, 25, new int[] { 1963, 1965 }, new string[] { "Lotus" }), new Racer("Jack", "Brabham", "Australia", 125, 14, new int[] { 1959, 1960, 1966 }, new string[] { "Cooper", "Brabham" }), new Racer("Denny", "Hulme", "New Zealand", 112, 8, new int[] { 1967 }, new string[] { "Brabham" }), new Racer("Graham", "Hill", "UK", 176, 14, new int[] { 1962, 1968 }, new string[] { "BRM", "Lotus" }), new Racer("Jochen", "Rindt", "Austria", 60, 6, new int[] { 1970 }, new string[] { "Lotus" }), new Racer("Jackie", "Stewart", "UK", 99, 27, new int[] { 1969, 1971, 1973 }, new string[] { "Matra", "Tyrrell" }), new Racer("Emerson", "Fittipaldi", "Brazil", 143, 14, new int[] { 1972, 1974 }, new string[] { "Lotus", "McLaren" }), new Racer("James", "Hunt", "UK", 91, 10, new int[] { 1976 }, new string[] { "McLaren" }), new Racer("Mario", "Andretti", "USA", 128, 12, new int[] { 1978 }, new string[] { "Lotus" }), new Racer("Jody", "Scheckter", "South Africa", 112, 10, new int[] { 1979 }, new string[] { "Ferrari" }), new Racer("Alan", "Jones", "Australia", 115, 12, new int[] { 1980 }, new string[] { "Williams" }), new Racer("Keke", "Rosberg", "Finland", 114, 5, new int[] { 1982 }, new string[] { "Williams" }), new Racer("Niki", "Lauda", "Austria", 173, 25, new int[] { 1975, 1977, 1984 }, new string[] { "Ferrari", "McLaren" }), new Racer("Nelson", "Piquet", "Brazil", 204, 23, new int[] { 1981, 1983, 1987 }, new string[] { "Brabham", "Williams" }), new Racer("Ayrton", "Senna", "Brazil", 161, 41, new int[] { 1988, 1990, 1991 }, new string[] { "McLaren" }), new Racer("Nigel", "Mansell", "UK", 187, 31, new int[] { 1992 }, new string[] { "Williams" }), new Racer("Alain", "Prost", "France", 197, 51, new int[] { 1985, 1986, 1989, 1993 }, new string[] { "McLaren", "Williams" }), new Racer("Damon", "Hill", "UK", 114, 22, new int[] { 1996 }, new string[] { "Williams" }), new Racer("Jacques", "Villeneuve", "Canada", 165, 11, new int[] { 1997 }, new string[] { "Williams" }), new Racer("Mika", "Hakkinen", "Finland", 160, 20, new int[] { 1998, 1999 }, new string[] { "McLaren" }), new Racer("Michael", "Schumacher", "Germany", 287, 91, new int[] { 1994, 1995, 2000, 2001, 2002, 2003, 2004 }, new string[] { "Benetton", "Ferrari" }), new Racer("Fernando", "Alonso", "Spain", 252, 32, new int[] { 2005, 2006 }, new string[] { "Renault" }), new Racer("Kimi", "Räikkönen", "Finland", 230, 20, new int[] { 2007 }, new string[] { "Ferrari" }), new Racer("Lewis", "Hamilton", "UK", 166, 43, new int[] { 2008, 2014, 2015 }, new string[] { "McLaren", "Mercedes" }), new Racer("Jenson", "Button", "UK", 283, 15, new int[] { 2009 }, new string[] { "Brawn GP" }), new Racer("Sebastian", "Vettel", "Germany", 156, 42, new int[] { 2010, 2011, 2012, 2013 }, new string[] { "Red Bull Racing" }) };
[Serializable] public class Team { public Team(string name, params int[] years) { this.Name = name; this.Years = years; } public string Name { get; private set; } public int[] Years { get; private set; } }
//冠军团队List public static List<Team> ChampionTeams = new List<Team>() { new Team("Vanwall", 1958), new Team("Cooper", 1959, 1960), new Team("Ferrari", 1961, 1964, 1975, 1976, 1977, 1979, 1982, 1983, 1999, 2000, 2001, 2002, 2003, 2004, 2007, 2008), new Team("BRM", 1962), new Team("Lotus", 1963, 1965, 1968, 1970, 1972, 1973, 1978), new Team("Brabham", 1966, 1967), new Team("Matra", 1969), new Team("Tyrrell", 1971), new Team("McLaren", 1974, 1984, 1985, 1988, 1989, 1990, 1991, 1998), new Team("Williams", 1980, 1981, 1986, 1987, 1992, 1993, 1994, 1996, 1997), new Team("Benetton", 1995), new Team("Renault", 2005, 2006), new Team("Brawn GP", 2009), new Team("Red Bull Racing", 2010, 2011, 2012, 2013), new Team("Mercedes", 2014, 2015) };
以上が.NET Framework - LINQ9 クラス演算子で使用されるサンプル コードの詳細内容です。詳細については、PHP 中国語 Web サイトの他の関連記事を参照してください。