Sum - 集合应为数字类型集合，求其和；不延迟

/// <summary>

        

/// Sum - 集合应为数字类型集合，求其和；不延迟

        

/// </summary>

        

void Summary_Sum()

        {

                

int i = (from a

in _ary

                                 select a.Length).Sum();

                result.InnerHtml += i.ToString() +

"<br />";

                result.InnerHtml +=

"<br />";

        }

 

运行结果

87

Min - 返回集合的最小值；不延迟

/// <summary>

        

/// Min - 返回集合的最小值；不延迟

        

/// </summary>

        

void Summary_Min()

        {

                

int i = (from a

in _ary

                                 select a.Length).Min();

                result.InnerHtml += i.ToString() +

"<br />";

                result.InnerHtml +=

"<br />";

        }

 

运行结果

2

Max - 返回集合的最大值；不延迟

/// <summary>

        

/// Max - 返回集合的最大值；不延迟

        

/// </summary>

        

void Summary_Max()

        {

                

int i = (from a

in _ary

                                 select a.Length).Max();

                result.InnerHtml += i.ToString() +

"<br />";

                result.InnerHtml +=

"<br />";

        }

 

运行结果

12

Average - 集合应为数字类型集合，求其平均值；不延迟

/// <summary>

        

/// Average - 集合应为数字类型集合，求其平均值；不延迟

        

/// </summary>

        

void Summary_Average()

        {

                

double d = (from a

in _ary

                                        select a.Length).Average();

                result.InnerHtml += d.ToString() +

"<br />";

                result.InnerHtml +=

"<br />";

        }

 

运行结果

5.8

Aggregate - 根据输入的表达式获取一个聚合值；不延迟

/// <summary>

        

/// Aggregate - 根据输入的表达式获取一个聚合值；不延迟

        

/// </summary>

        

void Summary_Aggregate()

        {

                

// 以下算法的Aggregate相当于Sum

                

double d = (from a

in _ary

                                        select a.Length).Aggregate((x, y) => x + y);

                result.InnerHtml += d.ToString() +

"<br />";

                result.InnerHtml +=

"<br />";

        }

 

运行结果

87

Cast - 将集合转换为强类型集合；延迟

/// <summary>

        

/// Cast - 将集合转换为强类型集合；延迟

        

/// </summary>

        

void Summary_Cast()

        {

                ArrayList al =

new ArrayList();

                al.Add(

"asp.net");

                al.Add(

"csharp");

                al.Add(

"xhtml");

                var list = al.Cast<

string>();

                

foreach (

string s

in list)

                {

                        result.InnerHtml += s +

"<br />";

                }

                result.InnerHtml +=

"<br />";

        }

 

运行结果

asp.net

csharp

xhtml

DefaultIfEmpty - 查询结果为空则返回默认值；延迟

/// <summary>

        

/// DefaultIfEmpty - 查询结果为空则返回默认值；延迟

        

/// </summary>

        

void Summary_DefaultIfEmpty()

        {

                var list = (from a

in _ary

                                        where a.Length > 100

                                        select a).DefaultIfEmpty(

"xxx");

                

foreach (

string s

in list)

                {

                        result.InnerHtml += s +

"<br />";

                }

                result.InnerHtml +=

"<br />";

        }

 

运行结果

xxx

SequenceEqual - 判断两个集合是否相同；不延迟

/// <summary>

        

/// SequenceEqual - 判断两个集合是否相同；不延迟

        

/// </summary>

        

void Summary_SequenceEqual()

        {

                

bool b = (from a

in _ary

                                    where a.Length > 10

                                    select a).SequenceEqual(from a

in _ary

                                                                                    where a.Length > 10

                                                                                    select a);

                result.InnerHtml += b.ToString() +

"<br />";

                result.InnerHtml +=

"<br />";

        }

 

运行结果

True

OfType - 过滤集合中的指定类型；延迟

/// <summary>

        

/// OfType - 过滤集合中的指定类型；延迟

        

/// </summary>

        

void Summary_OfType()

        {

                

object[] objects = { 1,

"a", 2,

"b", 3,

"c" };

                var list = objects.OfType<

string>();

                

foreach (

string s

in list)

                {

                        result.InnerHtml += s +

"<br />";

                }

                result.InnerHtml +=

"<br />";

        }

 

运行结果

a

b

c

ToArray - 将集合转换为数组；不延迟

/// <summary>

        

/// ToArray - 将集合转换为数组；不延迟

        

/// </summary>

        

void Summary_ToArray()

        {

                

string[] ary = (from p

in _ctx.Products

                                                where p.ProductName.Length > 30

                                                select p.ProductName).ToArray();

                

foreach (

string s

in ary)

                {

                        result.InnerHtml += s +

"<br />";

                }

                result.InnerHtml +=

"<br />";

        }

 

运行结果

Jack's New England Clam Chowder

Louisiana Fiery Hot Pepper Sauce

Original Frankfurter grüne So?e

Uncle Bob's Organic Dried Pears

ToList - 将集合转换为List<T>集合；不延迟

/// <summary>

        

/// ToList - 将集合转换为List<T>集合；不延迟

        

/// </summary>

        

void Summary_ToList()

        {

                var list = (from a

in _ary

                                        where a.Length > 10

                                        select a).ToList();

                

foreach (

string s

in list)

                {

                        result.InnerHtml += s +

"<br />";

                }

                result.InnerHtml +=

"<br />";

        }

 

运行结果

silverlight

asp.net ajax

ToDictionary - 将集合转换为<K, V>集合；不延迟

/// <summary>

        

/// ToDictionary - 将集合转换为<K, V>集合；不延迟

        

/// </summary>

        

void Summary_ToDictionary()

        {

                var dic = (from p

in _ctx.Products

                                     where p.ProductName.Length > 30

                                     select p).ToDictionary(p => p.ProductID);

                

foreach (var p

in dic)

                {

                        result.InnerHtml += p.Key +

"：" + p.Value.ProductName +

"<br />";

                }

                result.InnerHtml +=

"<br />";

        }

 

运行结果

7：Uncle Bob's Organic Dried Pears

41：Jack's New England Clam Chowder

65：Louisiana Fiery Hot Pepper Sauce

77：Original Frankfurter grüne So?e

OK

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