LINQ to object--immediate execution of enumerable class methods

In the previous approach to the enumerable class that LINQ to object--deferred, the next step is to say the enumerable class method that LINQ to object--immediately executes.

1.ToArray sequence Conversion array

list<string> names_list =Newlist<string> {"Zhang San","Fan Bing","Li bingbing","Michael Jackson","John Doe","Harry","Zhao Liu","Tianqi" }; string[] Takenames_arry =names_list.            ToArray (); string[] Takenames_arry2 = ( fromNameinchnames_listSelectName). Take (4).            ToArray (); foreach(varNameinchTakenames_arry2)            {Console.WriteLine (name); } Console.WriteLine ("----------------------------"); Console.readkey ();

Operation Result:

2.ToList sequence converted to list<t>

            string[] Names_array = {"Zhang San","Fan Bing","Li bingbing","Michael Jackson","John Doe","Harry","Zhao Liu","Tianqi" }; List<string> takenames_list =Names_array.            ToList (); List<string> Takenames_list2 = ( fromNameinchNames_arraySelectName). Skip (4).            ToList (); foreach(varNameinchtakenames_list2)            {Console.WriteLine (name); } Console.WriteLine ("----------------------------"); Console.readkey ();

Operation Result:

3.todictionary Converting a sequence to a generic dictionary<tkey,tvalue>

4.ToLookup is used to convert a sequence to a generic lookup<tkey,tvalue>

5.sequenceequal Comparison of two sequences for equality

            bool sequence_equal = Names_array. SequenceEqual (names_list);             bool sequence_equal2 = Names_array. Skip (1). Take (2). SequenceEqual (names_list. Take (32));            Console.WriteLine ("{0},{1}", Sequence_equal, sequence_equal2);            Console.WriteLine ("----------------------------");            Console.readkey ();

Operation Result:

6. First returns a sequence that satisfies a conditional element

            var first_name = Names_array. First ();             var 3 );            Console.WriteLine ("{0},{1}", first_name, first_name2);            Console.WriteLine ("----------------------------");            Console.readkey ();

Operation Result:

7.FirstOrDefault return sequence first satisfies the condition element, if not found, returns the default value

            var first_or_default_name = Names_array. FirstOrDefault ();             var " 123 " );            Console.WriteLine ("{0},{1}", First_or_default_name, First_or_default_ NAME2);            Console.WriteLine ("----------------------------");            Console.readkey ();

Operation Result:

8. Last returns a sequence that satisfies the condition element

            var last_name = Names_array. Last ();             var 3 );            Console.WriteLine ("{0},{1}", last_name, last_name2);            Console.WriteLine ("----------------------------");            Console.readkey ();

Operation Result:

9.LastOrDefault Returns the last element of the sequence that satisfies the condition and returns the default value if not found

            var last_or_default_name = Names_array. LastOrDefault ();             var " 123 " );            Console.WriteLine ("{0},{1}", Last_or_default_name, Last_or_default_ NAME2);            Console.WriteLine ("----------------------------");            Console.readkey ();

Operation Result:

Ten. Single Returns the only element in the sequence, note: If the sequence contains multiple elements, a run error is raised

            Try            {                varSingle_name =Names_array.            Single (); }            Catch(Exception ex) {Console.WriteLine (ex).            Message); } Console.WriteLine ("----------------------------"); varSingle_name2 = Names_array. Single (n = n = ="Zhang San"); Console.WriteLine ("{0}", single_name2); Console.WriteLine ("----------------------------"); Console.readkey ();

Operation Result:

Singleordefault Find the element that satisfies a certain condition in the sequence, note that if the sequence is empty, the default value is returned, and if the sequence contains more than one element, a run error is raised

            Try            {                varSingle_or_default_name = enumerable.empty<int>().                Singleordefault (); Console.WriteLine ("{0}", single_or_default_name);//no error, return default value if sequence is empty            }            Catch(Exception ex) {Console.WriteLine (ex).            Message); } Console.WriteLine ("----------------------------"); Try            {                varSingle_or_default_name2 =Names_array.                Singleordefault (); Console.WriteLine ("{0}", single_or_default_name2);//error, sequence contains multiple line errors            }            Catch(Exception ex) {Console.WriteLine (ex).            Message); } Console.WriteLine ("----------------------------"); varSingle_or_default_name3 = enumerable.empty<string> (). DefaultIfEmpty ("Default Value").            Singleordefault (); Console.WriteLine ("{0}", Single_or_default_name3); Console.WriteLine ("----------------------------"); varSingle_or_default_name4 = Names_array. Singleordefault (n = n = ="123"); Console.WriteLine ("{0}", Single_or_default_name4); Console.WriteLine ("----------------------------"); Console.readkey ();

Operation Result:

ElementAt . Gets the element at the specified index

            var element_at_name = Names_array. ElementAt (3);            Console.WriteLine ("{0}", element_at_name);            Console.WriteLine ("----------------------------");            Console.readkey ();

Operation Result:

Elementatordefault Gets the element at the specified index, and returns the default value of the element type if the index is exceeded

            var element_at_or_default_name = Names_array. Elementatordefault (5);             var element_at_or_default_name2 = Names_array. Elementatordefault (ten);            Console.WriteLine ("{0},{1}", Element_at_or_default_name, Element_at_or_ DEFAULT_NAME2);            Console.WriteLine ("----------------------------");            Console.readkey ();

Operation Result:

All elements in the all sequence meet the criteria

Whether an element in the any sequence exists or satisfies a condition

Contains Determines whether an element is in a sequence

Thecount sequence contains the number of elements

LongCount . Gets the number of elements of a Int64 type

Aggregate to accumulate sequence elements

Sums ofSum sequences

Average sequence Average

Minimum value ofmin sequence

Max value of themax sequence

To be Continued ...

LINQ to object--immediate execution of enumerable class methods