排序操作符

LinqStudy.Test/LinqToObject/OrderTest.cs

@@ -0,0 +1,300 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Linq;
+using System.Linq.Expressions;
+
+using Xunit;
+
+namespace LinqStudy.Test.LinqToObject
+{
+    /// <summary>
+    /// 排序操作符
+    /// 数据源为null时，均引发ArgumentNullException异常
+    /// </summary>
+    public class OrderTest
+    {
+        #region OrderBy
+
+        /// <summary>
+        /// OrderBy：升序排序(从小到大)；延迟执行
+        /// </summary>
+        [Fact]
+        public void OrderBy_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=33 },
+                new Person(){ Id = 3, Name = "李四", Age=65 },
+                new Person(){ Id = 2, Name = "王五", Age=17 },
+            };
+
+            var oprationItem = peoples.OrderBy(p => p.Id);
+
+            var firtId = oprationItem.First().Id;
+            var lastId = oprationItem.Last().Id;
+
+            Assert.Equal(1,firtId);
+            Assert.Equal(3, lastId);
+        }
+
+        /// <summary>
+        /// 延迟执行
+        /// </summary>
+        [Fact]
+        public void OrderBy_Delay_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=33 },
+                new Person(){ Id = 3, Name = "李四", Age=65 },
+                new Person(){ Id = 2, Name = "王五", Age=17 },
+            };
+
+            var oprationItem = peoples.OrderBy(p => p.Id);
+
+            var addItem = new Person() { Id = 4, Name = "赵立", Age = 87 };
+            peoples.Add(addItem);
+
+            var firtId = oprationItem.First().Id;
+            var lastId = oprationItem.Last().Id;
+
+            Assert.Equal(1, firtId);
+            Assert.Equal(4, lastId);
+        }
+
+        /// <summary>
+        /// 重载：自定义Comparable比较器
+        /// </summary>
+        [Fact]
+        public void OrderBy_CustomComparable_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=33 },
+                new Person(){ Id = 3, Name = "李四", Age=65 },
+                new Person(){ Id = 2, Name = "王五", Age=17 },
+            };
+
+            var oprationItem = peoples.OrderBy(p => p, new PersonComparer());
+
+            var firtId = oprationItem.First().Id;
+            var lastId = oprationItem.Last().Id;
+
+            Assert.Equal(1, firtId);
+            Assert.Equal(3, lastId);
+        }
+        #endregion
+
+        #region OrderByDescending
+        /// <summary>
+        /// OrderByDescending：降序排序(从大到步)；延迟执行
+        /// </summary>
+        [Fact]
+        public void OrderByDescending_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=33 },
+                new Person(){ Id = 3, Name = "李四", Age=65 },
+                new Person(){ Id = 2, Name = "王五", Age=17 },
+            };
+
+            var oprationItem = peoples.OrderByDescending(p => p.Id);
+
+            var firtId = oprationItem.First().Id;
+            var lastId = oprationItem.Last().Id;
+
+            Assert.Equal(3, firtId);
+            Assert.Equal(1, lastId);
+        }
+
+        /// <summary>
+        /// 延迟执行
+        /// </summary>
+        [Fact]
+        public void OrderByDescending_Delay_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=33 },
+                new Person(){ Id = 3, Name = "李四", Age=65 },
+                new Person(){ Id = 2, Name = "王五", Age=17 },
+            };
+
+            var oprationItem = peoples.OrderByDescending(p => p.Id);
+
+            var addItem = new Person() { Id = 4, Name = "赵立", Age = 87 };
+            peoples.Add(addItem);
+
+            var firtId = oprationItem.First().Id;
+            var lastId = oprationItem.Last().Id;
+
+            Assert.Equal(4, firtId);
+            Assert.Equal(1, lastId);
+        }
+
+        /// <summary>
+        /// 重载：自定义Comparable比较器
+        /// </summary>
+        [Fact]
+        public void OrderByDescending_CustomComparable_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=33 },
+                new Person(){ Id = 3, Name = "李四", Age=65 },
+                new Person(){ Id = 2, Name = "王五", Age=17 },
+            };
+
+            var oprationItem = peoples.OrderByDescending(p => p, new PersonComparer());
+
+            var firtId = oprationItem.First().Id;
+            var lastId = oprationItem.Last().Id;
+
+            Assert.Equal(3, firtId);
+            Assert.Equal(1, lastId);
+        }
+        #endregion
+
+        #region ThenBy
+        /// <summary>
+        /// ThenBy：按次要关键字，进行升序排序(从小到大)；延迟执行
+        /// </summary>
+        [Fact]
+        public void ThenBy_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=44 },
+                new Person(){ Id = 1, Name = "李四", Age=33 },
+                new Person(){ Id = 2, Name = "王五", Age=22 },
+                new Person(){ Id = 2, Name = "赵立", Age=11 },
+            };
+
+            //先按Id排序，Id相同的，再按年龄排序。
+            var oprationItem = peoples.OrderBy(p => p.Id).ThenBy(p => p.Age).Select(p => p.Name);
+            var expected = new List<string>() { "李四", "张三", "赵立", "王五" };
+
+            Assert.Equal(expected, oprationItem);
+        }
+
+        /// <summary>
+        /// 延迟执行
+        /// </summary>
+        [Fact]
+        public void ThenBy_Delay_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=44 },
+                new Person(){ Id = 1, Name = "李四", Age=33 },
+                new Person(){ Id = 2, Name = "王五", Age=22 },
+                new Person(){ Id = 2, Name = "赵立", Age=11 },
+            };
+
+            var oprationItem = peoples.OrderBy(p => p.Id).ThenBy(p => p.Age);
+            
+            var addItme = new Person() { Id = 1, Name = "刘能", Age = 2 };
+            peoples.Add(addItme);
+
+            var actual = oprationItem.Select(p => p.Name).ToList();
+            var expected = new List<string>() { "刘能", "李四", "张三", "赵立", "王五" };
+
+            Assert.Equal(expected, actual);
+        }
+
+        /// <summary>
+        /// 重载：自定义Comparable比较器
+        /// </summary>
+        [Fact]
+        public void ThenBy_CustomComparable_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=44 },
+                new Person(){ Id = 1, Name = "李四", Age=33 },
+                new Person(){ Id = 2, Name = "王五", Age=22 },
+                new Person(){ Id = 2, Name = "赵立", Age=11 },
+            };
+
+            var oprationItem = peoples.OrderBy(p => p, new PersonComparer()).ThenBy(p=>p.Age,Comparer<int>.Default);
+
+            var actual = oprationItem.Select(p => p.Name).ToList();
+            var expected = new List<string>() {"李四", "张三", "赵立", "王五" };
+
+            Assert.Equal(expected, actual);
+        }
+        #endregion
+
+        #region ThenByDescending
+        /// <summary>
+        /// ThenByDescending：按次要关键字，进行降序排序(从大到小)；延迟执行
+        /// </summary>
+        [Fact]
+        public void ThenByDescending_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=44 },
+                new Person(){ Id = 1, Name = "李四", Age=33 },
+                new Person(){ Id = 2, Name = "王五", Age=22 },
+                new Person(){ Id = 2, Name = "赵立", Age=11 },
+            };
+
+            //先按Id排序，Id相同的，再按年龄排序。
+            var oprationItem = peoples.OrderBy(p => p.Id).ThenByDescending(p => p.Age).Select(p => p.Name);
+            var expected = new List<string>() {"张三","李四","王五", "赵立"};
+
+            Assert.Equal(expected, oprationItem);
+        }
+
+        /// <summary>
+        /// 延迟执行
+        /// </summary>
+        [Fact]
+        public void ThenByDescending_Delay_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=44 },
+                new Person(){ Id = 1, Name = "李四", Age=33 },
+                new Person(){ Id = 2, Name = "王五", Age=22 },
+                new Person(){ Id = 2, Name = "赵立", Age=11 },
+            };
+
+            var oprationItem = peoples.OrderBy(p => p.Id).ThenByDescending(p => p.Age);
+
+            var addItme = new Person() { Id = 1, Name = "刘能", Age = 2 };
+            peoples.Add(addItme);
+
+            var actual = oprationItem.Select(p => p.Name).ToList();
+            var expected = new List<string>() { "张三", "李四", "刘能", "王五","赵立" };
+
+            Assert.Equal(expected, actual);
+        }
+
+        /// <summary>
+        /// 重载：自定义Comparable比较器
+        /// </summary>
+        [Fact]
+        public void ThenByDescending_CustomComparable_Test()
+        {
+            List<Person> peoples = new List<Person>()
+            {
+                new Person(){ Id = 1, Name = "张三", Age=44 },
+                new Person(){ Id = 1, Name = "李四", Age=33 },
+                new Person(){ Id = 2, Name = "王五", Age=22 },
+                new Person(){ Id = 2, Name = "赵立", Age=11 },
+            };
+
+            var oprationItem = peoples.OrderBy(p => p, new PersonComparer()).ThenByDescending(p => p.Age, Comparer<int>.Default);
+
+            var actual = oprationItem.Select(p => p.Name).ToList();
+            var expected = new List<string>() { "张三","李四",  "王五", "赵立",};
+
+            Assert.Equal(expected, actual);
+        }
+        #endregion
+    }
+}

LinqStudy.Test/LinqToObject/QuantifierTest.cs

@@ -281,8 +281,8 @@ namespace LinqStudy.Test.LinqToObject
             var people = new Person() { Id = 3, Name = "小清闲", Age = 88 };
 
             //自定义比较器：Id相同即为同一个对象
-            PersonEqualId equalId = new PersonEqualId();
-            var anyQuery = peoples.Contains(people, new PersonEqualId());
+            PersonEqualityComparerById equalId = new PersonEqualityComparerById();
+            var anyQuery = peoples.Contains(people, new PersonEqualityComparerById());
 
             //比较器相等，即包含
             Assert.True(anyQuery);

LinqStudy.Test/LinqToObject/SequenceEqualTest.cs

@@ -192,7 +192,7 @@ namespace LinqStudy.Test.LinqToObject
                 new Person(){Id=1,Name="李四",Age=20},
             };
 
-            Assert.True(sequence1.SequenceEqual(sequence2, new PersonEqual()));
+            Assert.True(sequence1.SequenceEqual(sequence2, new PersonEqualityComparer()));
         }
     }
 }

LinqStudy.Test/LinqToObject/标准查询操作符.md

@@ -18,7 +18,7 @@
 
 ## 分组操作符
 
-## 串联操作符
+## 集合操作符
 
 ## 聚合操作符
 
@@ -31,8 +31,11 @@
 ## 相等操作符
 
 ## 量词操作符
+    Any
 
-## 分割操作符
+    All
+
+## 分区操作符
     Take 返回序列中,从0开始的连续指定项数据子序列；延迟执行。
 
     TakeWhile 

LinqStudy/Models/PersonCompare.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+
+namespace LinqStudy
+{
+    /// <summary>
+    /// Person±È½ÏÆ÷£ºIdΪ±È½Ï±ê×¼
+    /// </summary>
+    public class PersonComparer : IComparer<Person>
+    {
+        int IComparer<Person>.Compare(Person x, Person y)
+        {
+            int compareResult = 0;
+
+            if (x == null && y == null)
+            {
+                compareResult = 0;
+            }
+
+            else if (x == null)
+            {
+                compareResult = 1;
+            }
+            else if (y == null)
+            {
+                compareResult = -1;
+            }
+            else
+            {
+                if (x.Id == y.Id)
+                {
+                    compareResult = 0;
+                }
+                else if (x.Id > y.Id)
+                {
+                    compareResult = 1;
+                }
+                else
+                {
+                    compareResult = -1;
+                }
+            }
+
+            return compareResult;
+        }
+    }
+}

LinqStudy/Models/PersonEqualityComparer.cs

@@ -5,10 +5,10 @@ using System.Text;
 namespace LinqStudy
 {
     /// <summary>
-    /// Person自定义比较器
+    /// Person 自定义相等比较器
     /// 各属性均同，则相等.有一个Null值则不相等。
     /// </summary>
-    public class PersonEqual : IEqualityComparer<Person>
+    public class PersonEqualityComparer : IEqualityComparer<Person>
     {
         bool IEqualityComparer<Person>.Equals(Person x, Person y)
         {

LinqStudy/Models/PersonEqualityComparerById.cs

@@ -5,10 +5,10 @@ using System.Text;
 namespace LinqStudy
 {
     /// <summary>
-    /// Person 自定义ID比较器
+    /// Person 自定义ID相等比较器
     /// Id相同，则视为相同
     /// </summary>
-    public class PersonEqualId : IEqualityComparer<Person>
+    public class PersonEqualityComparerById : IEqualityComparer<Person>
     {
         bool IEqualityComparer<Person>.Equals(Person x, Person y)
         {