LINQ3

Метод Union
public static System.Collections.Generic.IEnumerable
Union
(this System.Collections.Generic.IEnumerable
first, System.Collections.Generic.IEnumerable
second);

Метод Union
int[] ints1 = { 5, 3, 9, 7, 5, 9, 3, 7 };
int[] ints2 = { 8, 3, 6, 4, 4, 9, 1, 0 };
IEnumerable
union = ints1.Union(ints2);
foreach (int num in union)
{
Console.Write("{0} ", num);
}

Метод Union
public bool Equals(ProductA other)
{
if (other is null)
return false; return this.Name == other.Name && this.Code == other.Code;
}
public override bool Equals(object obj) => Equals(obj as ProductA);
public override int GetHashCode() => (Name, Code).GetHashCode();

Метод Union
IEnumerable
union =
store1.Union(store2);
foreach (var product in union)
Console.WriteLine(product.Name + " " + product.Code);

Метод Intersect
public static System.Collections.Generic.IEnumerable
Intersect
(this System.Collections.Generic.IEnumerable
first, System.Collections.Generic.IEnumerable
second, System.Collections.Generic.IEqualityComparer
comparer);

Метод Intersect
public static System.Collections.Generic.IEnumerable
Intersect
(this System.Collections.Generic.IEnumerable
first, System.Collections.Generic.IEnumerable
second);

Метод Except
public static System.Collections.Generic.IEnumerable
Except
(this System.Collections.Generic.IEnumerable
first, System.Collections.Generic.IEnumerable
second);

Метод Except
double[] numbers1 = { 2.0, 2.0, 2.1, 2.2, 2.3, 2.3, 2.4, 2.5 };
double[] numbers2 = { 2.2 };
IEnumerable
onlyInFirstSet = numbers1.Except(numbers2);
foreach (double number in onlyInFirstSet)
Console.WriteLine(number);

Метод Except
public static System.Collections.Generic.IEnumerable
Except
(this System.Collections.Generic.IEnumerable
first, System.Collections.Generic.IEnumerable
second, System.Collections.Generic.IEqualityComparer
comparer);

Метод Contains
public static bool Contains
(this System.Collections.Generic.IEnumerable
source, TSource value);
public static bool Contains
(this System.Collections.Generic.IEnumerable
source, TSource value, System.Collections.Generic.IEqualityComparer
comparer);

Метод Single
public static TSource Single
(this System.Collections.Generic.IEnumerable
source, Func
predicate);
public static TSource Single
(this System.Collections.Generic.IEnumerable
source);

Метод Single
string[] fruits = { "apple", "banana", "mango",
"orange", "passionfruit", "grape" };
string fruit1 = fruits.Single(fruit => fruit.Length > 10);
Console.WriteLine(fruit1);

Метод Single
string[] fruits1 = { "orange" };
string fruit1 = fruits1.Single();
Console.WriteLine(fruit1);

Метод SingleOrDefault
public static TSource SingleOrDefault
(this System.Collections.Generic.IEnumerable
source);
public static TSource SingleOrDefault
(this System.Collections.Generic.IEnumerable
source, Func
predicate);

Метод Any
public static bool Any
(this System.Collections.Generic.IEnumerable
source);
List
numbers = new List { 1, 2 };
bool hasElements = numbers.Any();
Console.WriteLine("The list {0} empty.",
hasElements ? "is not" : "is");

Метод Any
public static bool Any
(this System.Collections.Generic.IEnumerable
source, Func
predicate);
Pet[] pets = {
new Pet { Name="Barley", Age=8, Vaccinated=true },
new Pet { Name="Boots", Age=4, Vaccinated=false },
new Pet { Name="Whiskers", Age=1, Vaccinated=false }
};
bool unvaccinated = pets.Any(p => p.Age > 1 && p.Vaccinated == false);

Метод All
public static bool All
(this System.Collections.Generic.IEnumerable
source, Func
predicate);
Pet[] pets = {
new Pet { Name="Barley", Age=10 },
new Pet { Name="Boots", Age=4 },
new Pet { Name="Whiskers", Age=6 } };
bool allStartWithB = pets.All(pet => pet.Name.StartsWith("B"));

Метод SequenceEqual
public static bool SequenceEqual
(this System.Collections.Generic.IEnumerable
first, System.Collections.Generic.IEnumerable
second);
List
pets1 = new List
{ pet1, pet2 };
List
pets2 = new List
{ pet1, pet2 };
bool equal = pets1.SequenceEqual(pets2);

Метод SequenceEqual
public static bool SequenceEqual
(this System.Collections.Generic.IEnumerable
first, System.Collections.Generic.IEnumerable
second, System.Collections.Generic.IEqualityComparer
comparer);

Метод SequenceEqual
class ProductComparer : IEqualityComparer
{
public bool Equals(Product x, Product y)
{
if (Object.ReferenceEquals(x, y)) return true;
if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null))
return false;
return x.Code == y.Code && x.Name == y.Name;
}

Метод SequenceEqual (продолжение)
public int GetHashCode(Product product)
{
if (Object.ReferenceEquals(product, null)) return 0;
int hashProductName = product.Name == null ? 0 : product.Name.GetHashCode();
int hashProductCode = product.Code.GetHashCode();
return hashProductName ^ hashProductCode;
}
}

Метод OfType
public static System.Collections.Generic.IEnumerable
OfType
(this System.Collections.IEnumerable source);

Метод OfType
System.Collections.ArrayList fruits = new System.Collections.ArrayList(4);
fruits.Add("Mango");fruits.Add("Orange");
fruits.Add("Apple");fruits.Add(3.0);fruits.Add("Banana");
IEnumerable
query1 = fruits.OfType
();
Console.WriteLine("Elements of type 'string' are:");
foreach (string fruit in query1)
{
Console.WriteLine(fruit);
}

Метод Cast
public static System.Collections.Generic.IEnumerable
Cast
(this System.Collections.IEnumerable source);
System.Collections.ArrayList fruits = new System.Collections.ArrayList(); fruits.Add("mango"); fruits.Add("apple"); fruits.Add("lemon");
IEnumerable
query = fruits.Cast
().OrderBy(fruit => fruit).Select(fruit => fruit);

Метод перевода
public static TSource[] ToArray
(…);
public static System.Collections.Generic.Dictionary
ToDictionary
(…);
public static System.Collections.Generic.List ToList
(…);
public static System.Collections.Generic.HashSet
ToHashSet
(…);

Метод Aggregate
public static TAccumulate Aggregate
(this System.Collections.Generic.IEnumerable
source, TAccumulate seed, Func
func);
int[] ints = { 4, 8, 8, 3, 9, 0, 7, 8, 2 };
int numEven = ints.Aggregate(0, (total, next) =>
next % 2 == 0 ? total + 1 : total);
Console.WriteLine("The number of even integers is: {0}", numEven);

Метод Join
public static System.Collections.Generic.IEnumerable
Join
(this System.Collections.Generic.IEnumerable
outer, System.Collections.Generic.IEnumerable
inner, Func
outerKeySelector, Func
innerKeySelector, Func
resultSelector);

Метод Join
List
people = new List
{ magnus, terry, charlotte };
List pets = new List
{ barley, boots, whiskers, daisy };
var query = people.Join(pets,
person => person,
pet => pet.Owner,
(person, pet) => new { OwnerName = person.Name, Pet = pet.Name });

Метод GroupJoin
public static System.Collections.Generic.IEnumerable
GroupJoin
(this System.Collections.Generic.IEnumerable
outer, System.Collections.Generic.IEnumerable
inner, Func
outerKeySelector, Func
innerKeySelector, Func
,TResult> resultSelector);

Метод GroupJoin
List
people = new List
{ magnus, terry, charlotte };
List pets = new List
{ barley, boots, whiskers, daisy };
var query = people.GroupJoin(pets,
person => person,
pet => pet.Owner,
(person, petCollection) => new {
OwnerName = person.Name,
Pets = petCollection.Select(pet => pet.Name) });

Метод GroupBy
public static System.Collections.Generic.IEnumerable
> GroupBy
(this System.Collections.Generic.IEnumerable
source, Func
keySelector, Func
elementSelector);