c# 기초구문 업데이트 완료

ExY.Linq/ExY.Linq.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

ExY.Linq/Program.cs

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+internal class Program
+{
+    private static void Main(string[] args)
+    {
+        var db = new DataBase { DBName = "mydb"};
+
+        // 쿼리식 표현
+        var v = from ord in db.Orders
+                where ord.Customer_ID == "FRANS"
+                orderby ord.Order_Date ascending
+                select ord;
+
+        // 메서드식 표현1
+        var w = db.Orders.Where(order => order.Customer_ID == "FRANS").Select(o => o);
+
+        // 메서드식 표현2
+        // 위의 메서드식 표현1의 Select()메서드는 동일데이타를
+        // 변형없이 리턴하므로 생략가능
+        var x = db.Orders.Where(order => order.Customer_ID == "FRANS");
+
+        x.Select((item, index) => new { IDX = index, ITEM = item });
+
+        //기타 확장메서드
+        x.First();
+        x.FirstOrDefault();
+        x.Last();
+        var l = x.ToList();
+        l.ForEach(item => Console.WriteLine(item.Customer_ID));
+        x.Select(item => item.Order_Date).Distinct();
+        
+    }
+}
+
+class DataBase
+{
+    public string DBName = string.Empty;
+    public List<Order> Orders = new();
+}
+
+class Order
+{
+    public string Customer_ID = string.Empty;
+    public DateTime Order_Date;
+    public List<string> Items = new();
+}