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LINQ (Language Integrated Query)
LINQ provides a unified way to query and manipulate data from different data sources. It introduces a powerful set of features for querying arrays, collections, XML, and databases using a consistent syntax.
Basic LINQ Queries
LINQ offers two syntax styles: query syntax (similar to SQL) and method syntax (using extension methods).
csharp
// Query syntax
var query = from num in numbers
where num > 5
orderby num
select num;
// Method syntax
var result = numbers
.Where(n => n > 5)
.OrderBy(n => n)
.Select(n => n);
Common LINQ Operations
LINQ provides a rich set of operations for working with collections.
csharp
// Filtering
var filtered = numbers.Where(n => n % 2 == 0);
// Ordering
var ordered = names.OrderBy(n => n);
var descending = names.OrderByDescending(n => n);
// Projection
var selected = people.Select(p => p.Name);
// Aggregation
var sum = numbers.Sum();
var avg = numbers.Average();
var count = numbers.Count();