arrays, generic conversion symbols

1. The OfType convert symbol can be a mixed type in an array. Presents a single type. For example:

Var numbers=new object[]{1, "string", "string", 2,3};

Foreach (var asint in numbers. Oftype<int> ()) {will only extract data of type int}

1. ToArray converts the result set of a query that contains only one column of values into an array of select. Toarray<arrayname[]> ();
2. Cast conversion symbol, does not throw an exception array.cast<int> ()
3. AsEnumerable will force those objects that implement IEnumerable to try the behavior of the IEnumerable interface

Mylist<t> temp=new Mylist<t> can enforce IEnumerable as long as the IEnumerable is implemented

Ienumerable<t> tem=temp. AsEnumerable (). Where (canshu=>canshu== "string value")

1. Tolist<t> (); Converting query results to list<t> allows us to add extra stuff to the result set
2. ToDictionary converts a Ienumerable<t> object, such as the result returned by a LINQ query, to a Idictionary<key,value> object. (Convert list<t> to idictionary<key,value>)

arrays, generic conversion symbols