LINQ系列：限制操作符

public static IEnumerable<TSource> Where<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate);

public static IEnumerable<TSource> Where<TSource>(this IEnumerable<TSource> source, Func<TSource, int, bool> predicate);

var products = from p in context.Products
               where p.UnitPrice > 10m
               select p;

var products = context.Products
    .Where(p => p.UnitPrice > 10m);

var products = from p in context.Products
               where p.UnitPrice > 10m && p.ProductName.StartsWith("LINQ")
               select p;

var products = context.Products
    .Where(p => p.UnitPrice > 10m && p.ProductName.StartsWith("LINQ"));

int[] fibonacci = new int[] { 1, 1, 2, 3, 5, 8, 13, 21 };
var expr = fibonacci.Where((f, index) => f > 1 && index > 3);
foreach (var item in expr)
{
    Console.WriteLine(item);
}