methods

.Any() - returns boolean.

The LINQ Any() method checks if at least one element in a collection satisfies a condition—or if the collection has any elements at all.

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.All()

• true if all elements match the condition. false if any one element fails the condition.

example

int[] numbers = { 2, 4, 6, 8 };

bool allEven = numbers.All(n => n % 2 == 0);  // returns true

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use Count() without parameters to get the total number of elements, or pass a predicate (like n => n > 25) to count only those that match a condition.

example:

int[] numbers = { 10, 20, 30, 40, 50 }; // Count all elements int totalCount = numbers.Count(); // Count elements greater than 25 int countGreaterThan25 = numbers.Count(n => n > 25);

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The Contains() method checks whether a sequence contains a specified element and returns a boolean result.

example:

 string[] fruits = { "apple", "banana", "mango", "orange" };

        // Check if "mango" exists in the array

        bool hasMango = fruits.Contains("mango");

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string[] names = { "Zara", "Adam", "John", "Bella" };

// Sort names in ascending order

var sortedNames = names.OrderBy(name => name);

OrderByDescending() if you want to sort in reverse order:

var descendingNames = names.OrderByDescending(name => name);

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Min

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Max

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Average

int[] numbers = { 10, 20, 30, 40, 50 }; 

double avg = numbers.Average();

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double averageMarks = students.Average(s => s.Marks);

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Sum

int[] numbers = { 10, 20, 30, 40, 50 };

        // Using LINQ Sum method

        int total = numbers.Sum();

//--- products.Sum(p=>p.Price);

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ElementAt(index) for IEnumerable<int>

to avoid exception use ElementAtOrDefault(index) 

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FirstOrDefault()

LastOrDefault()

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Single()

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SingleOrDefault()

This method returns the only element that matches a condition, or the default value (null for reference types) if no such element exists. It throws an exception if more than one match is found.

var users = new List { "Alice", "Bob", "Charlie" }; // This will return "Bob" string result = users.SingleOrDefault(u => u == "Bob");

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Where

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Take(int), TakeLast(int)

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 TakeWhile()

int[] numbers = { 10, 20, 30, 60, 40, 50 };

var result = numbers.TakeWhile(n => n < 50);

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Skip(int), SkipLast(int), SkipWhile(int)

numbers.Skip(2).Take(2)

numbers.SkipWhile(number => number < 20)

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OfType<T>

ArrayList items = new ArrayList();

items.Add("hello"); items.Add(42); items.Add("world"); items.Add(3.14); 

// Filter only strings 

var strings = items.OfType<string>();

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Distinct()

List<int> numbers = new List<int>() { 1, 2, 3, 2, 4, 3, 5 }; 

var distinctNumbers = numbers.Distinct();

O/P:  { 1,2,3,4,5 }

SyntaxEditor Code Snippet

public static IEnumerable<T> GetCollectionWithMostDuplicates<T>(IEnumerable<IEnumerable<T>> collections)

{

    return collections.OrderBy

                (collection => collection.Count() - collection.Distinct().Count())

                .ThenByDescending(collection=>collection.Count())

                .LastOrDefault();

}

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Append()  & Prepend()

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Concat() & Union()

example

numbers1.Concat(numbers2)

num1.Union(num2) -- remove duplicates

var unionofpets = pets1.Union(pets, PetEqualityByIdComparer);// - union by two reference collection

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