Element, quantifier and partitioning operators — LINQ — Language Integrated Query

4. Element, quantifier and partitioning operators

Basic★ Must knowLesson 4 of 12

Operator	Empty sequence	More than one match
`First()`	throws	returns first
`FirstOrDefault()`	default/null	returns first
`Single()`	throws	throws
`SingleOrDefault()`	default/null	throws
`Last()` / `LastOrDefault()`	throws / default	returns last
`ElementAt(i)` / `ElementAtOrDefault(i)`	throws / default	—

csharp

bool anyOut = products.Any(p => p.Stock == 0);     // stops at first match
bool allPriced = products.All(p => p.Price > 0);
bool hasMouse = products.Select(p => p.Name).Contains("Mouse");

var page2 = products.OrderBy(p => p.Id).Skip(10).Take(10);
var whileCheap = products.OrderBy(p => p.Price).TakeWhile(p => p.Price < 10000);
foreach (var batch in products.Chunk(100)) { /* process 100 at a time (.NET 6) */ }
var cheapest = products.MinBy(p => p.Price);       // .NET 6 — returns the element, not the value

Use Any() instead of Count() > 0 — Any stops at the first element.