クエリ式を書いてみた。

QueryTest.cs

using System;
using System.Linq;
namespace ConsoleApplication
{
	class Program{
		public enum Job{
			knight,magician,axman,archer,witch,swordman,
		}
		static void Main (string[] args) {
			var persons = new []{
				new {name = "a",	Job = Job.archer,	HP = 1,	Luck = 1.3,	like = "cherry" },
				new {name = "a",	Job = Job.magician,	HP = 2,	Luck = 1.2,	like = "banana" },
				new {name = "b",	Job = Job.knight,	HP = 3,	Luck = 1.1,	like = "lemon" },
				new {name = "b",	Job = Job.axman,	HP = 1,	Luck = 1.3,	like = "peach" },
				new {name = "c",	Job = Job.magician,	HP = 2,	Luck = 1.2,	like = "orange" },
				new {name = "c",	Job = Job.witch,	HP = 3,	Luck = 1.1,	like = "orange" },
				new {name = "a",	Job = Job.witch,	HP = 2,	Luck = 1.6,	like = "apple" },
				new {name = "e",	Job = Job.magician,	HP = 5,	Luck = 1.1,	like = "lemon" },
				new {name = "d",	Job = Job.archer,	HP = 8,	Luck = 1.3,	like = "pine" },
			};
			var items = new []{
				new {name = "banana",	heal = 20},
				new {name = "apple",	heal = 32},
				new {name = "cherry",	heal = 53},
				new {name = "peach",	heal = 25},
				new {name = "pine",		heal = 89},
				new {name = "orange",	heal = 57},
				new {name = "lemon",	heal = 11},
			};

			// origin
			Console.WriteLine ("origin:");
			foreach (var a in persons) {
				Console.WriteLine (a);
			}
			// sort
			Console.WriteLine ("\nname,Job,HP:");
			var nameJobHP = from x in persons
			          orderby x.name ,x.Job,x.HP
			        select x;
			foreach (var a in nameJobHP) {
				Console.WriteLine (a);
			}
			Console.WriteLine ("\nJob Luck HP:");
			var JobLickHP = from x in persons
			          orderby x.Job,x.Luck,x.HP descending
					select x;
			foreach (var a in JobLickHP) {
				Console.WriteLine (a);
			}

			// group by
			Console.WriteLine ("\n group by HP");
			var groupByHP = from x in persons
			                group x by x.HP
//			                into grouped
//			                where grouped.Key >= 3 // filter
//							select grouped;
			            	;
			foreach (var a in groupByHP) {
				Console.WriteLine ("HP:"+a.Key +" persons are..");
				foreach (var b in a) {
					Console.WriteLine ("\t"+b);
				}
			}

			// create new object
			Console.WriteLine ("\nif person like item, HP will..:");
			var allpattern = 
				from man in persons
				from item in items
				let newName = man.name +"(" + man.Job.ToString() +")" + " with " + item.name
				let newHP = man.like == item.name ? man.HP + item.heal * man.Luck : man.HP + item.heal
				select new {name = newName,HealedHP = newHP}
			;
			foreach (var a in allpattern) {
				Console.WriteLine (a);
			}
			// wereで書く
			Console.WriteLine ("\nlist up liked == item.name:where");
			var likePattern = 
				from man in persons
				from item in items
				where man.like == item.name
				let newName = man.name +"(" + man.Job.ToString() +")" + " with " + item.name
				let newHP = man.HP + item.heal * man.Luck
				select new {name = newName,HealedHP = newHP}
			;
			foreach (var a in likePattern) {
				Console.WriteLine (a);
			}

			// joinで書く
			Console.WriteLine ("\nlist up by only liked item:join");
			var writeByJoin = 
				from man in persons
				join item in items on man.like equals item.name
				let newName = man.name +"(" + man.Job.ToString() +")" + " with " + item.name
				let newHP = man.HP + item.heal * man.Luck
				select new {name = newName,HealedHP = newHP}
			;
			foreach (var a in writeByJoin) {
				Console.WriteLine (a);
			}

			// join intoで書く
			Console.WriteLine ("\nwho like fruite?:join into");
			var fruiteLike = 
				from item in items
				join man in persons on item.name equals man.like into ps
				select new {name = item.name,persons = ps.Select( y => y.name + "(" + y.Job.ToString() + ")" )}
			;
			foreach (var a in fruiteLike) {
				string p = "";
				foreach (string name in a.persons) {
					p += name + ",\t";
				}
				Console.WriteLine (string.Format("name:\t{0}\tliked:{1}",a.name,p));
			}
		}
	}
}