How to use List in C#? Summary of basic usage of List

　What about List in C#? The List class is the generic equivalent of the ArrayList class, which implements the IList generic interface using an array whose size can be dynamically increased as needed. Next, the editor will introduce some basic and simple usage of List.

Benefits of generics: It adds great efficiency and flexibility to writing object-oriented programs using the C# language. There is no forced boxing and unboxing of value types, or downcasting of reference types, so performance is improved.

Performance Note: When deciding to use IList or the ArrayList class (both have similar functionality), remember that the IList class performs better in most cases and is type-safe. If you use a reference type for type T of the IList class, the behavior of the two classes is exactly the same. However, if you use a value type for type T, you need to consider implementation and boxing issues.

Basic common methods of C# List:

1. Statement:

1. List mList = new List();

T is the element type in the list, now take the string type as an example ：

　 List mList = new List();

　 2. List testList =new List (IEnumerable collection);

Create a List with a collection as a parameter ：

　 string[] temArr = { "Ha", "Hunter", "Tom", "Lily", "Jay", "Jim", "Kuku", "Locu"};

　 List testList = new List(temArr);

　　2. Add elements:

　1. List. Add(T item) Add an element

　Example:

　mList.Add("John");

　2 , List. AddRange(IEnumerable collection) adds a set of elements

Example:

　string[] temArr = {"Ha","Hunter","Tom","Lily","Jay","Jim" ,"Kuku","Locu"};mList.AddRange(temArr);

　3. Insert(intindex, T item); Add an element at the index position

　Example:

　mList.Insert(1,"Hei ");

3. Traverse the elements in the List:

　　foreach(TelementinmList)T的类型与mList声明时一样
　　{
　　Console.WriteLine(element);
　　}
　　例：
　　foreach(stringsinmList)
　　{
　　Console.WriteLine(s);
　　}

4. Delete elements:

1. List. Remove(T item) deletes a value

Example:

mList.Remove("Hunter ");

　 2. List. RemoveAt(intindex); Delete the element whose subscript is index

　 Example:

　 mList.RemoveAt(0);

3. List. RemoveRange(intindex,intcount);

Starting from the subscript index, delete count elements

Example:

mList.RemoveRange(3, 2);

5. Determine whether an element is in the List:

List. Contains(T item) Return true or false, very practical

Example:

　　if(mList.Contains("Hunter"))
　　{
　　Console.WriteLine("There is Hunter in the list");
　　}
　　else
　　{
　　mList.Add("Hunter");
　　Console.WriteLine("Add Hunter successfully.");
　　}

6. Sort the elements in the List:

List. Sort () defaults to the first letter of the element in ascending order

Example:

mList.Sort ();

7. Reverse the order of elements in List:

List. Reverse () can be used in conjunction with List. Sort () to achieve the desired effect

Example:

mList.Sort();

8. Clear the List:

List. Clear ()

Example:

mList.Clear(); Example:
N in tcount = mlist.count ();

console.writeline ("the num of elements in the list:"+count); You guys are helpful.

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