ArrayList与泛型类
多线程的使用方法之一
using System.Threading;
Thread th = new Thread (mc.Test4);
th.Start ();
Thread th2 = new Thread (mc.Test5);
th2.Start ();
集合:ArrayList属于非泛型集合
ArrayList是一个数组集合.
List
它属于动态改变长度的数组集合,不需要我们管理.
///
///非泛型集合添加元素演示
///
public void Test()
{
ArrayList al = new ArrayList ();
//演示添加非对象元素
al.Add ("刘德华");
al.Add ("张学友");
al.Add (1);
//遍历数组
for (int i = 0; i < al.Count; i++) {
Console.WriteLine (al[i]);
}
foreach (var item in al) {
Console.WriteLine (item);
}
}
///
///泛型集合添加元素演示
///
public void Test2()
{
//这个T是占位符，不代表任何意义
List list=new List();
list.Add ("刘德华");
list.Add ("张学友");
}
///
///演示非泛型集合添加10000000个元素所耗费的时间
///
public void Test4()
{
ArrayList a1 = new ArrayList ();
Stopwatch sw = new Stopwatch ();
sw.Start ();
for (int i = 0; i < 10000000; i++) {
a1.Add (i);
}
sw.Stop ();
Console.WriteLine ("非泛型集合ArrayList添加100万元素所耗费的时间{0}",sw.Elapsed);
}
///
///演示泛型集合添加10000000个元素所耗费的时间
///
public void Test5()
{
Stopwatch sw = new Stopwatch ();
sw.Start ();
List l1 = new List ();
for (int i = 0; i < 10000000; i++) {
l1.Add (i);
}
sw.Stop ();
Console.WriteLine ("泛型集合ArrayList添加100万元素所耗费的时间{0}",sw.Elapsed);
}
///
///非泛型集合排序/倒排与泛型基本相同
///
public void Test6()
{
// ArrayList al = new ArrayList ();
// int[] arr = { 1, 2, 3, 4,3, 6, 7 };
// al.AddRange (arr);
//
// //倒排
// al.Reverse ();
// //排序
// al.Sort ();
// foreach (var item in al) {
// Console.WriteLine (al);
// }
List li=new List();
HashSet hs=new HashSet();
Hashtable ht = new Hashtable ();
ht.Add (1, 3);
ht.Add (2, 5);
hs.Add (1);
hs.Add (2);
li.AddRange (hs);
foreach (var item in li) {
Console.WriteLine (item);
}
}
///
///研究ArrayList的capacity
///
public void Test7()
{
ArrayList al = new ArrayList (3);
Console.WriteLine (al.Capacity);
al.Add (1);
al.Add (2);
al.Add (3);
al.Add (3);
Console.WriteLine (al.Capacity);
}
///
///研究ArrayList的insert()
///
/// The command-line arguments.
public void Test8()
{
ArrayList a1 = new ArrayList ();
int[] arr = { 1, 2, 3, 4,3, 6, 7 };
a1.AddRange (arr);
//插入指定的索引处
a1.Insert (1,10);
//移除第一个出现的3
a1.Remove(3);
//下标
a1.RemoveAt(2);
foreach (var item in a1) {
Console.WriteLine (item);
}
}
//T只是占位符,T只可以赋值,但是不能运算+ - * /
//struct表示限定的是值类型
// public void Swap(ref T num1,ref T num2) where T:struct
// {
// T temp=default(T);
// temp = num1;
// num1 = num2;
// num2 = temp;
// }
//演示引用类型限定
// public void Swap(ref T num1,ref T num2) where T:class
// {
// T temp=default(T);
// temp = num1;
// num1 = num2;
// num2 = temp;
// }
public T Swap(ref T num1,ref T num2) where T:IComparable
{
if (num1.CompareTo (num2) < 0) {
return num2;
} else {
return num1;
}
}
//返回为0意味着相等
//1表示降序
//-1表示升序
int a=10;
int b = 9;
int s=a.CompareTo (b);
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