c#中 各種 集合 總結
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一.先來說說數組的不足（也可以說集合與數組的區別）：1.數組是固定大小的，不能伸縮。雖然System.Array.Resize這個泛型方法可以重設數組大小，但是該方法是重新建立新設定大小的數組，用的是舊數組的元素初始化。隨後以前的數組就廢棄！而集合卻是可變長的2.數組要聲明元素的類型，集合類的元素類型卻是object.3.數組可讀可寫不能聲明唯讀數組。集合類可以提供ReadOnly方法以唯讀方式使用集合。4.數組要有整數下標才能訪問特定的元素，然而很多時候這樣的下標並不是很有用。二.下面講述6種常用集合1.ArrayList類using System;using System.Collections.Generic;using System.Text;using System.Collections;namespace ConsoleApplication1...{ class Program ...{ static void Main(string[] args) ...{ ArrayList al = new ArrayList(); al.Add(100);//單個添加 foreach (int number in new int[6] ...{ 9, 3, 7, 2, 4, 8 }) ...{ al.Add(number);//集體添加方法一//清清月兒 http://blog.csdn.net/21aspnet/ } int[] number2 = new int[2] ...{ 11,12 }; al.AddRange(number2);//集體添加方法二 al.Remove(3);//移除值為3的 al.RemoveAt(3);//移除第3個 ArrayList al2 = new ArrayList(al.GetRange(1, 3));//新ArrayList只取舊ArrayList一部份 Console.WriteLine("遍曆方法一:"); foreach (int i in al)//不要強制轉換 ...{ Console.WriteLine(i);//遍曆方法一 } Console.WriteLine("遍曆方法二:"); for (int i = 0; i != al2.Count; i++)//數組是length ...{ int number = (int)al2[i];//一定要強制轉換 Console.WriteLine(number);//遍曆方法二 } } }}2.Stack類棧，後進先出。push方法入棧，pop方法出棧。using System;using System.Collections.Generic;using System.Text;using System.Collections;namespace ConsoleApplication1...{ class Program ...{ static void Main(string[] args) ...{ Stack sk = new Stack(); Stack sk2 = new Stack(); foreach (int i in new int[4] ...{ 1, 2, 3, 4 }) ...{ sk.Push(i);//填充 sk2.Push(i); } foreach (int i in sk) ...{ Console.WriteLine(i);//遍曆 } sk.Pop(); Console.WriteLine("Pop"); foreach (int i in sk) ...{ Console.WriteLine(i); } sk2.Peek();//彈出最後一項不刪除//清清月兒 http://blog.csdn.net/21aspnet/ Console.WriteLine("Peek"); foreach (int i in sk2) ...{ Console.WriteLine(i); } while (sk2.Count != 0) ...{ int i = (int)sk2.Pop();//清空 sk2.Pop();//清空 } Console.WriteLine("清空"); foreach (int i in sk2) ...{ Console.WriteLine(i); } } }}3.Queue類隊列，先進先出。enqueue方法入隊列，dequeue方法出隊列。using System;using System.Collections.Generic;using System.Text;using System.Collections;namespace ConsoleApplication1...{ class Program ...{ static void Main(string[] args) ...{ Queue qu = new Queue(); Queue qu2 = new Queue(); foreach (int i in new int[4] ...{ 1, 2, 3, 4 }) ...{ qu.Enqueue(i);//填充 qu2.Enqueue(i); } foreach (int i in qu) ...{ Console.WriteLine(i);//遍曆 } qu.Dequeue(); Console.WriteLine("Dequeue"); foreach (int i in qu) ...{ Console.WriteLine(i); } qu2.Peek();//彈出最後一項不刪除 Console.WriteLine("Peek"); foreach (int i in qu2) ...{ Console.WriteLine(i); } while (qu2.Count != 0) ...{ int i = (int)qu2.Dequeue();//清空 qu2.Dequeue();//清空 } Console.WriteLine("清空"); foreach (int i in qu2) ...{ Console.WriteLine(i); } } }}4.Hashtable類雜湊表，名-值對。類似於字典(比數組更強大)。雜湊表是經過最佳化的，訪問下標的對象先散列過。如果以任意類型索引值訪問其中元素會快於其他集合。GetHashCode()方法返回一個int型資料，使用這個鍵的值產生該int型資料。雜湊表擷取這個值最後返回一個索引，表示帶有給定散列的資料項目在字典中儲存的位置。using System;using System.Collections.Generic;using System.Text;using System.Collections;namespace ConsoleApplication1...{ class Program ...{ public static void Main() ...{ // Creates and initializes a new Hashtable. Hashtable myHT = new Hashtable(); myHT.Add("one", "The"); myHT.Add("two", "quick"); myHT.Add("three", "brown"); myHT.Add("four", "fox"); // Displays the Hashtable.//清清月兒 http://blog.csdn.net/21aspnet/ Console.WriteLine("The Hashtable contains the following:"); PrintKeysAndValues(myHT); } public static void PrintKeysAndValues(Hashtable myHT) ...{ foreach (string s in myHT.Keys) Console.WriteLine(s); Console.WriteLine(" -KEY- -VALUE-"); foreach (DictionaryEntry de in myHT) Console.WriteLine(" {0}: {1}", de.Key, de.Value); Console.WriteLine(); } }}5.SortedList類與雜湊表類似，區別在於SortedList中的Key數組排好序的。using System;using System.Collections.Generic;using System.Text;using System.Collections;namespace ConsoleApplication1...{ class Program ...{ public static void Main() ...{ SortedList sl = new SortedList(); sl["c"] = 41; sl["a"] = 42; sl["d"] = 11; sl["b"] = 13; foreach (DictionaryEntry element in sl) ...{ string s = (string)element.Key; int i = (int)element.Value; Console.WriteLine("{0},{1}",s,i); } } }}6.NameValueCollection類官方給NameValueCollection定義為特殊集合一類，在System.Collections.Specialized下。System.Collections.Specialized下還有HybridDicionary類，建議少於10個元素用HybridDicionary，當元素增加會自動轉為HashTable。System.Collections.Specialized下還有HybridDicionary類，字串集合。System.Collections.Specialized下還有其他類大家可以各取所需！言歸正轉主要說NameValueCollection，HashTable 和 NameValueCollection很類似但是他們還是有區別的，HashTable 的KEY是唯一性，而NameValueCollection則不唯一！using System;using System.Collections.Generic;using System.Collections;using System.Collections.Specialized;namespace ConsoleApplication1...{ class Program ...{ static void Main(string[] args) ...{ System.Collections.Hashtable ht = new System.Collections.Hashtable(); ht.Add("DdpMDisplaySeq".Trim(), "Display Sequence".Trim()); ht.Add("DdpMNameChi".Trim(), "Name (Chinese)".Trim()); ht.Add("DdpMNameEng".Trim(), "Name (English)".Trim()); ht.Add("Comment".Trim(), "Comment".Trim()); ht.Add("DdpMMarketCode".Trim(), "Market Code".Trim()); foreach (object key in ht.Keys) ...{ Console.WriteLine("{0}/{1} {2},{3}", key, ht[key], key.GetHashCode(), ht[key].GetHashCode()); } Console.WriteLine(" ");//清清月兒 http://blog.csdn.net/21aspnet/ NameValueCollection myCol = new NameValueCollection(); myCol.Add("DdpMDisplaySeq".Trim(), "Display Sequence".Trim()); myCol.Add("DdpMNameChi".Trim(), "Name (Chinese)".Trim()); myCol.Add("DdpMNameChi".Trim(), "Name (English)".Trim()); myCol.Add("Comment".Trim(), "Comment".Trim()); myCol.Add("DdpMMarketCode".Trim(), "Market Code".Trim()); foreach (string key in myCol.Keys) ...{ Console.WriteLine("{0}/{1} {2},{3}", key, myCol[key], key.GetHashCode(), myCol[key].GetHashCode()); } } }}
