C#的6种常用集合类大比拼【月儿原创】
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C#的6种常用集合类大比拼【月儿原创】
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C#的6種常用集合類大比拼
作者：清清月兒
主頁：http://blog.csdn.net/21aspnet/?????????? 時(shí)間：2007.6.27?
說明：MSDN沒有說出幾種集合類其間的區(qū)別，當(dāng)然欲知更多細(xì)節(jié)可參考MSDN。
一.先來說說數(shù)組的不足（也可以說集合與數(shù)組的區(qū)別）：
1.數(shù)組是固定大小的，不能伸縮。雖然System.Array.Resize這個(gè)泛型方法可以重置數(shù)組大小，但是該方法是重新創(chuàng)建新設(shè)置大小的數(shù)組，用的是舊數(shù)組的元素初始化。隨后以前的數(shù)組就廢棄！而集合卻是可變長的
2.數(shù)組要聲明元素的類型，集合類的元素類型卻是object.
3.數(shù)組可讀可寫不能聲明只讀數(shù)組。集合類可以提供ReadOnly方法以只讀方式使用集合。
4.數(shù)組要有整數(shù)下標(biāo)才能訪問特定的元素，然而很多時(shí)候這樣的下標(biāo)并不是很有用。集合也是數(shù)據(jù)列表卻不使用下標(biāo)訪問。很多時(shí)候集合有定制的下標(biāo)類型，對于隊(duì)列和棧根本就不支持下標(biāo)訪問！
?
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(gè)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(gè)
????????????ArrayList?al2?=?new?ArrayList(al.GetRange(1,?3));//新ArrayList只取舊ArrayList一部份
????????????Console.WriteLine("遍歷方法一:");
????????????foreach?(int?i?in?al)//不要強(qiáng)制轉(zhuǎn)換
????????????...{
????????????????Console.WriteLine(i);//遍歷方法一
????????????}
????????????Console.WriteLine("遍歷方法二:");
????????????for?(int?i?=?0;?i?!=?al2.Count;?i++)//數(shù)組是length
????????????...{
????????????????int?number?=?(int)al2[i];//一定要強(qiáng)制轉(zhuǎn)換
????????????????Console.WriteLine(number);//遍歷方法二
????????????}
????????}
????}
}
?
2.Stack類
棧，后進(jìn)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);//遍歷
????????????}
????????????sk.Pop();
????????????Console.WriteLine("Pop");
????????????foreach?(int?i?in?sk)
????????????...{
????????????????Console.WriteLine(i);
????????????}
????????????
????????????sk2.Peek();//彈出最后一項(xiàng)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(duì)列，先進(jìn)先出。enqueue方法入隊(duì)列，dequeue方法出隊(duì)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);//遍歷
????????????}
????????????qu.Dequeue();
????????????Console.WriteLine("Dequeue");
????????????foreach?(int?i?in?qu)
????????????...{
????????????????Console.WriteLine(i);
????????????}
????????????
????????????qu2.Peek();//彈出最后一項(xiàng)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
哈希表，名-值對。類似于字典(比數(shù)組更強(qiáng)大)。哈希表是經(jīng)過優(yōu)化的，訪問下標(biāo)的對象先散列過。如果以任意類型鍵值訪問其中元素會(huì)快于其他集合。GetHashCode()方法返回一個(gè)int型數(shù)據(jù)，使用這個(gè)鍵的值生成該int型數(shù)據(jù)。哈希表獲取這個(gè)值最后返回一個(gè)索引，表示帶有給定散列的數(shù)據(jù)項(xiàng)在字典中存儲(chǔ)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
與哈希表類似，區(qū)別在于SortedList中的Key數(shù)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，建議少于10個(gè)元素用HybridDicionary，當(dāng)元素增加會(huì)自動(dòng)轉(zhuǎn)為HashTable。
System.Collections.Specialized下還有HybridDicionary類，字符串集合。
System.Collections.Specialized下還有其他類大家可以各取所需！
言歸正轉(zhuǎn)主要說NameValueCollection，HashTable 和 NameValueCollection很類似但是他們還是有區(qū)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());
????????????}
????????}
????}
}
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