static void Main(string[] args)
{
// declare products array which includes categories for each product
var products = new[] {
new {name="salon shampoo", price=15.99d, categories = new[]{
new {name="bath"},
new {name="luxury"}
}
},
new {name="soap", price=1.33d, categories = new[]{
new {name="bath"}
}
},
new {name="asiago bread", price=5.99d, categories = new[]{
new {name="luxury"},
new {name="grocery"}
}
},
new {name="sugar 1kg", price=1.99d, categories = new[]{
new {name="grocery"}
}
}
};
// linq query to extract products less than $10 and of category "grocery"
var groceries = from p in products
where p.price < 10D && p.categories.Any(c => c.name == "grocery")
select p;
// Alternatively: "Fluent" syntax is more condensed:
// var groceries = products.Where(p => p.price < 10D &&
p.categories.Any(c => c.name == "grocery"));
//now iterate the result to display the selected product foreach (var product in result)
{
Console.Write(string.Format("\r\nProd:{0}, Price:{1} Categories:", product.name, product.price));
foreach (var category in product.categories)
{
Console.Write(category.name + " ");
}
}
//however SELECTMANY, can show the collection in a "flattened" list, while repeating parent items
var allProducts = products.SelectMany(p => p.categories, (p, c) =>
p.name + ", $" + p.price.ToString() + ", cat=" + c.name);
Console.WriteLine("All Products:" + string.Join("\r\n", allProducts.ToArray()));
var grocFlattened = groceries.SelectMany(p=>
p.categories,(p,c)=>p.name + ", $" + p.price.ToString() + ", cat=" + c.name);
Console.WriteLine("Groceries:" + string.Join("\r\n", grocFlattened.ToArray()));
//Groceries:
// asiago bread, $5.99, cat=luxury
// asiago bread, $5.99, cat=grocery
// sugar 1kg, $1.99, cat=grocery
}
SelectMany is very powerful and cool as it can "flatten" a collection, but otherwise works just like a Select statement.
