List of c #

List of c #
List

Generic set, which can replace ArrayList

Common Methods

List
  
    list = new List
   
    ();
   
  

Method Name	Function
Add ()	Add Element
AddRange	Add a set
ToArray ()	Convert a set to an array

An array has a method called ToList (), which can be used to convert an array into a set;

Why use list instead of ArrayList?

Packing and unpacking
Converting the value type to the reference type is called packing, and converting the reference type to the value type is called unpacking;
Packing and unpacking will be a running operation, which will take a long time for the program to run, and the generic set is generated at the Compilation Time of the specified type;
Check whether the two types are packed or unpacked. check whether there is an inheritance relationship between the two types. If there is an inheritance relationship, the packing operation may occur;

Class Name	Element type	Disassembly box?	Running time
List	Sure and unique	No	Relatively short
ArrayList	Not sure, there are many	Yes	Long time

Using System; using System. collections; using System. collections. generic; using System. diagnostics; using System. linq; using System. text; using System. threading. tasks; namespace List generic set {class Program {static void Main (string [] args) {ArrayList list = new ArrayList (); // ArrayList Program time: 00: 00: 00.1229805 // list program time: 00: 00: 00.0276141 // List
  
   
List = new List
   
    
(); List. add (0); list. add (0); Console. writeLine (list. count); Stopwatch sw = new Stopwatch (); sw. start (); for (int I = 0; I <1000000; I ++) {list. add (I);} sw. stop (); Console. writeLine ("program time:" + sw. elapsed); Console. readKey ();}}}