Class IEnumerableExtensions

IEnumerable 扩展方法

Inheritance

Object

IEnumerableExtensions

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Lett.Extensions

Assembly: Lett.Extensions.dll

Syntax

public static class IEnumerableExtensions

Methods

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ContainsAll<T>(IEnumerable<T>, IEnumerable<T>)

是否包含全部元素

this 是否包含 items 中全部元素

Declaration

public static bool ContainsAll<T>(this IEnumerable<T> this, IEnumerable<T> items)

Parameters

Type	Name	Description
IEnumerable<T>	this
IEnumerable<T>	items	需要进行判断的元素集合

Returns

Type	Description
Boolean

Type Parameters

Name	Description
T	集合中元素的类型

Examples

var arr    = new[] {"aa", "bb"};
var match  = new[] {"aa"};
var match2 = new[] {"aa", "bb"};
var match2 = new[] {"aa", "bb", "cc"};
var rs = arr.ContainsAll(match);    // true;
var rs2 = arr.ContainsAll(match2);  // true;
var rs3 = arr.ContainsAll(match3);  // false;

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`items` is null

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ContainsAny<T>(IEnumerable<T>, IEnumerable<T>)

是否包含任一元素

this 是否包含 items 中任一元素

Declaration

public static bool ContainsAny<T>(this IEnumerable<T> this, IEnumerable<T> items)

Parameters

Type	Name	Description
IEnumerable<T>	this
IEnumerable<T>	items	需要进行判断的元素集合

Returns

Type	Description
Boolean

Type Parameters

Name	Description
T	集合中元素的类型

Examples

var arr    = new[] {"aa", "bb"};
var match  = new[] {"aa", "bb"};
var match2 = new [] {"aa", "bb", "cc"};
var rs = arr.ContainsAny(match); // true
var rs2 = arr.ContainsAny(match2); // true

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`items` is null

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Distinct<T, TResult>(IEnumerable<T>, Func<T, TResult>)

返回序列中的非重复元素

Declaration

public static IEnumerable<T> Distinct<T, TResult>(this IEnumerable<T> this, Func<T, TResult> selector)

Parameters

Type	Name	Description
IEnumerable<T>	this
Func<T, TResult>	selector	选择器，选择用于比较的对象

Returns

Type	Description
IEnumerable<T>

Type Parameters

Name	Description
T
TResult

Examples

var input = new List<MyClass> {new MyClass {Age = 2, Name = "a"}, new MyClass {Age = 2, Name = "A"}, new MyClass {Age = 2, Name = "b"}};

var rs1 = input.Distinct(s => s.Name).ToList();

rs1.Count;      // 3
rs1[0].Name;    // "a"

var input = new List<MyClass> {new MyClass {Age = 2, Name = "a"}, new MyClass {Age = 2, Name = "A"}, new MyClass {Age = 2, Name = "b"}};

var rs2 = input.Distinct(s => s.Age).ToList();

rs2.Count;      // 1
rs2[0];         // "a"

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`selector` is null

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Distinct<T, TResult>(IEnumerable<T>, Func<T, TResult>, IEqualityComparer<TResult>)

返回序列中的非重复元素

Declaration

public static IEnumerable<T> Distinct<T, TResult>(this IEnumerable<T> this, Func<T, TResult> selector, IEqualityComparer<TResult> equalityComparer)

Parameters

Type	Name	Description
IEnumerable<T>	this
Func<T, TResult>	selector	选择器，选择用于比较的对象
IEqualityComparer<TResult>	equalityComparer	比较器

Returns

Type	Description
IEnumerable<T>

Type Parameters

Name	Description
T
TResult

Examples

var input = new List<MyClass> {new MyClass {Age = 2, Name = "a"}, new MyClass {Age = 2, Name = "A"}, new MyClass {Age = 2, Name = "b"}};

var rs1 = input.Distinct(s => s.Name, StringComparer.OrdinalIgnoreCase)
.ToList();

rs1.Count;      // 2
rs1[0].Name;    // "a"

var input = new List<MyClass> {new MyClass {Age = 2, Name = "a"}, new MyClass {Age = 2, Name = "A"}, new MyClass {Age = 2, Name = "b"}};

var rs2 = input.Distinct(s => s.Age, EqualityComparer<int>.Default)
.ToList();

rs2.Count;      // 1
rs2[0];         // "a"

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`selector` is null
ArgumentNullException	`equalityComparer` is null

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Duplicates<T, TResult>(IEnumerable<T>, Func<T, TResult>)

返回序列中重复的元素

Declaration

public static IEnumerable<TResult> Duplicates<T, TResult>(this IEnumerable<T> this, Func<T, TResult> selector)

Parameters

Type	Name	Description
IEnumerable<T>	this
Func<T, TResult>	selector	选择器，选择用于比较的对象

Returns

Type	Description
IEnumerable<TResult>

Type Parameters

Name	Description
T
TResult

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`selector` is null

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Duplicates<T, TResult>(IEnumerable<T>, Func<T, TResult>, IEqualityComparer<TResult>)

返回序列中重复的元素

Declaration

public static IEnumerable<TResult> Duplicates<T, TResult>(this IEnumerable<T> this, Func<T, TResult> selector, IEqualityComparer<TResult> equalityComparer)

Parameters

Type	Name	Description
IEnumerable<T>	this
Func<T, TResult>	selector	选择器，选择用于比较的对象
IEqualityComparer<TResult>	equalityComparer	比较器

Returns

Type	Description
IEnumerable<TResult>

Type Parameters

Name	Description
T
TResult

Examples

var input = new List<MyClass> {new MyClass {Age = 2, Name = "a"}, new MyClass {Age = 2, Name = "A"}, new MyClass {Age = 2, Name = "b"}};
var rs1   = input.Duplicates(s => s.Name, StringComparer.OrdinalIgnoreCase);
// rs1 = {"a"}

var input = new List<MyClass> {new MyClass {Age = 2, Name = "a"}, new MyClass {Age = 2, Name = "A"}, new MyClass {Age = 2, Name = "b"}};
var rs1   = input.Duplicates(s => s.Name);
// rs1 = {}

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`selector` is null
ArgumentNullException	`equalityComparer` is null

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ForEach<T>(IEnumerable<T>, Action<T>)

对指定集合的每个元素执行指定操作。

Declaration

public static void ForEach<T>(this IEnumerable<T> this, Action<T> action)

Parameters

Type	Name	Description
IEnumerable<T>	this
Action<T>	action	指定操作 T: 元素

Type Parameters

Name	Description
T	元素类型

Examples

var arr = new[] {"aa", "bb"};
var rs  = new List<string>();
arr.ForEach(str => rs.Add(str));
// rs[0] = "aa"
// rs[1] = "bb"

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`action` is null

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ForEach<T>(IEnumerable<T>, Action<Int32, T>)

对指定集合的每个元素执行指定操作。

Declaration

public static void ForEach<T>(this IEnumerable<T> this, Action<int, T> action)

Parameters

Type	Name	Description
IEnumerable<T>	this
Action<Int32, T>	action	指定操作 int: 数组元素的索引 T: 元素

Type Parameters

Name	Description
T	元素类型

Examples

var arr = new[] {"aa", "bb"};
var rs  = new Dictionary<int, string>();
arr.ForEach((index, str) => rs.Add(index, str));
// rs[0] = "aa"
// rs[1] = "bb"

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentNullException	`action` is null

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IsNullOrEmpty<T>(IEnumerable<T>)

是否空或空集合

Declaration

public static bool IsNullOrEmpty<T>(this IEnumerable<T> this)

Parameters

Type	Name	Description
IEnumerable<T>	this

Returns

Type	Description
Boolean

Type Parameters

Name	Description
T	集合中元素的类型

Examples

var arr = new[] {"aa", "bb"};
var rs = arr.IsNullOrEmpty(); // false

var arr2 = new string[] { };
var rs2 = arr.IsNullOrEmpty(); // true

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SplitBlock<T>(IEnumerable<T>, Int32)

分割成指定size的块

like this :
new[] {1, 2, 3, 4, 5, 6, 7}.SplitBlock(3); -> {{1, 2, 3}, {4, 5, 6}, {7}}

Declaration

public static IEnumerable<IEnumerable<T>> SplitBlock<T>(this IEnumerable<T> this, int size)

Parameters

Type	Name	Description
IEnumerable<T>	this
Int32	size	size

Returns

Type	Description
IEnumerable<IEnumerable<T>>

Type Parameters

Name	Description
T

Examples

var s = new[] {1, 2, 3, 4, 5, 6, 7};
var rs = s.Block(2);  // rs = {{1, 2}, {3, 4}, {5, 6}, {7}}
var rs2 = s.Block(3); // rs2 = {{1, 2, 3}, {4, 5, 6}, {7}}
var rs3 = s.Block(4); // rs3 = {{1, 2, 3, 4}, {5, 6, 7}}

Exceptions

Type	Condition
ArgumentNullException	`this` is null
ArgumentException	`size` less than 1

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ToFormatString<T>(IEnumerable<T>, String, Func<T, Object[]>)

格式化为字符串

Declaration

public static string ToFormatString<T>(this IEnumerable<T> this, string formatStr, Func<T, object[]> formatParams)

Parameters

Type	Name	Description
IEnumerable<T>	this
String	formatStr	格式化字符串，如："[{0}]"
Func<T, Object[]>	formatParams	格式化字符串参数，需要与格式化字符串对应

Returns

Type	Description
String

Type Parameters

Name	Description
T

Examples

var input = new List<string> {"aa", "bb", "cc", "dd"};
var rs = input.FormatString("[{0}]", s => new []{s});

// rs = "[aa][bb][cc][dd]"

var input2 = new Dictionary<string,object>
{
{"key1",1},
{"key2","value2"},
{"key3","value3"}
};

var rs2 = input2.FormatString("[{0} - {1}]\r\n", pair => new[] {pair.Key, pair.Value});

// rs2 = "[key1 - 1]\r\n[key2 - value2]\r\n[key3 - value3]\r\n"

Exceptions

Type	Condition
ArgumentNullException	`formatStr` 为空
FormatException