using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Linq.Expressions;
using Xunit;
namespace LinqStudy.Test.LinqToObject
{
///
/// 排序操作符
/// 数据源为null时,均引发ArgumentNullException异常
///
public class OrderTest
{
#region OrderBy
///
/// OrderBy:升序排序(从小到大);延迟执行
///
[Fact]
public void OrderBy_Test()
{
List peoples = new List()
{
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);
}
///
/// 延迟执行
///
[Fact]
public void OrderBy_Delay_Test()
{
List peoples = new List()
{
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);
}
///
/// 重载:自定义Comparable比较器
///
[Fact]
public void OrderBy_CustomComparable_Test()
{
List peoples = new List()
{
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
///
/// OrderByDescending:降序排序(从大到步);延迟执行
///
[Fact]
public void OrderByDescending_Test()
{
List peoples = new List()
{
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);
}
///
/// 延迟执行
///
[Fact]
public void OrderByDescending_Delay_Test()
{
List peoples = new List()
{
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);
}
///
/// 重载:自定义Comparable比较器
///
[Fact]
public void OrderByDescending_CustomComparable_Test()
{
List peoples = new List()
{
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
///
/// ThenBy:按次要关键字,进行升序排序(从小到大);延迟执行
///
[Fact]
public void ThenBy_Test()
{
List peoples = new List()
{
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() { "李四", "张三", "赵立", "王五" };
Assert.Equal(expected, oprationItem);
}
///
/// 延迟执行
///
[Fact]
public void ThenBy_Delay_Test()
{
List peoples = new List()
{
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() { "刘能", "李四", "张三", "赵立", "王五" };
Assert.Equal(expected, actual);
}
///
/// 重载:自定义Comparable比较器
///
[Fact]
public void ThenBy_CustomComparable_Test()
{
List peoples = new List()
{
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.Default);
var actual = oprationItem.Select(p => p.Name).ToList();
var expected = new List() {"李四", "张三", "赵立", "王五" };
Assert.Equal(expected, actual);
}
#endregion
#region ThenByDescending
///
/// ThenByDescending:按次要关键字,进行降序排序(从大到小);延迟执行
///
[Fact]
public void ThenByDescending_Test()
{
List peoples = new List()
{
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() {"张三","李四","王五", "赵立"};
Assert.Equal(expected, oprationItem);
}
///
/// 延迟执行
///
[Fact]
public void ThenByDescending_Delay_Test()
{
List peoples = new List()
{
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() { "张三", "李四", "刘能", "王五","赵立" };
Assert.Equal(expected, actual);
}
///
/// 重载:自定义Comparable比较器
///
[Fact]
public void ThenByDescending_CustomComparable_Test()
{
List peoples = new List()
{
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.Default);
var actual = oprationItem.Select(p => p.Name).ToList();
var expected = new List() { "张三","李四", "王五", "赵立",};
Assert.Equal(expected, actual);
}
#endregion
}
}