我只是想知道为什么我应该使用Any()
而不是Count()
?,如果我们以msdn为例:
class Pet
{
public string Name { get; set; }
public int Age { get; set; }
}
class Person
{
public string LastName { get; set; }
public Pet[] Pets { get; set; }
}
public static void AnyEx2()
{
List<Person> people = new List<Person>
{ new Person { LastName = "Haas",
Pets = new Pet[] { new Pet { Name="Barley", Age=10 },
new Pet { Name="Boots", Age=14 },
new Pet { Name="Whiskers", Age=6 }}},
new Person { LastName = "Fakhouri",
Pets = new Pet[] { new Pet { Name = "Snowball", Age = 1}}},
new Person { LastName = "Antebi",
Pets = new Pet[] { }},
new Person { LastName = "Philips",
Pets = new Pet[] { new Pet { Name = "Sweetie", Age = 2},
new Pet { Name = "Rover", Age = 13}} }
};
// Determine which people have a non-empty Pet array.
IEnumerable<string> names = from person in people
where person.Pets.AsQueryable().Any()
select person.LastName;
foreach (string name in names)
Console.WriteLine(name);
/* This code produces the following output:
Haas
Fakhouri
Philips
*/
}
如果我使用了怎么办:
IEnumerable<string> names = from person in people
where person.Pets.Count() > 0
select person.LastName;
它会给出相同的结果!, (我不认为它是为了简短或什么而创建的),有什么功能Any()
吗??