C#常用集合的使用
大多数集合都在System.Collections,System.Collections.Generic两个命名空间。其中System.Collections.Generic专门用于泛型集合。
针对特定类型的集合类型位于System.Collections.Specialized;命名空间;
线程安全的集合类位于System.Collections.Concurrent;命名空间。
下面是集合和列表实现的接口如下:
一、列表
- [Serializable]
- [DebuggerTypeProxy(typeof(Mscorlib_CollectionDebugView<>))]
- [DebuggerDisplay("Count = {Count}")]
- public class List<T> : IList<T>, ICollection<T>, IEnumerable<T>, IList, ICollection, IEnumerable
从这个可以看出,泛型集合List<T>实现了这么多接口,具体接口的信息可以通过工具查看。
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- List<String> list = new List<string>();
- list.Add("张三");
- list.Add("李四");
- list.Add("王五");
- list.Add("田六");
- list.Add("赵七");
- for (int i = 0; i < list.Count; i++)
- {
- Console.WriteLine("for循环:" + i.ToString() + "=" + list[i]);
- }
- list.RemoveAt(0);
- foreach (String item in list)
- {
- Console.WriteLine("foreach迭代:" + item);
- }
- list.AddRange(new String[] { "Hello1", "Hello2", "Hello3" });
- list.ForEach(Print);
- Console.Read();
- }
- private static void Print(String item)
- {
- Console.WriteLine("ForEach:" + item);
- }
- }
- }
二、队列
队列先进先出,一头进一头出,用Queue<T>实现
- [Serializable]
- [DebuggerTypeProxy(typeof(System_QueueDebugView<>))]
- [ComVisible(false)]
- [DebuggerDisplay("Count = {Count}")]
- public class Queue<T> : IEnumerable<T>, ICollection, IEnumerable
可以看出队列实现了集合的接口,迭代的接口
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- Queue<String> queue = new Queue<string>();
- //进队
- queue.Enqueue("张三");
- queue.Enqueue("李四");
- queue.Enqueue("王五");
- queue.Enqueue("田六");
- queue.Enqueue("赵七");
- foreach (String item in queue)
- {
- Console.WriteLine("foreach迭代:" + item);
- }
- //出队
- while (queue.Count > 0)
- {
- Console.WriteLine("出队:" + queue.Dequeue());
- }
- Console.Read();
- }
- }
- }
三、栈
栈:从同一边先进后出,用Stack<T>实现
- [DebuggerDisplay("Count = {Count}")]
- [DebuggerTypeProxy(typeof(System_StackDebugView<>))]
- [ComVisible(false)]
- public class Stack<T> : IEnumerable<T>, ICollection, IEnumerable
栈也是实现了集合接口与迭代接口的
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- Stack<String> stack = new Stack<string>();
- //进栈
- stack.Push("张三");
- stack.Push("李四");
- stack.Push("王五");
- stack.Push("田六");
- stack.Push("赵七");
- foreach (String item in stack)
- {
- Console.WriteLine("foreach迭代:" + item);
- }
- //出栈
- while (stack.Count > 0)
- {
- Console.WriteLine("出栈:" + stack.Pop());
- }
- Console.Read();
- }
- }
- }
四、链表
LinkedList是一个双向链表,链表有个有点,就是在链表中间插入、删除元素很快,但是查找中间与末尾的元素很慢,需要一个节点一个节点的去找。
- [Serializable]
- [DebuggerTypeProxy(typeof(System_CollectionDebugView<>))]
- [DebuggerDisplay("Count = {Count}")]
- [ComVisible(false)]
- public class LinkedList<T> : ICollection<T>, IEnumerable<T>, ICollection, IEnumerable, ISerializable, IDeserializationCallback
由此可见链表也是有集合的特性的,可以迭代,同时还有链表的特性
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- LinkedList<String> lList = new LinkedList<string>();
- LinkedListNode<String> node = new LinkedListNode<string>("root");
- lList.AddFirst(node);
- node = lList.AddAfter(node, "张三");
- node = lList.AddAfter(node, "李四");
- node = lList.AddAfter(node, "王五");
- node = lList.AddAfter(node, "田六");
- node = lList.AddAfter(node, "赵七");
- foreach (String item in lList)
- {
- Console.WriteLine("foreach迭代:" + item);
- }
- node = lList.First;
- Console.WriteLine("第一个元素:" + node.Value);
- node = lList.Last;
- Console.WriteLine("最后一个元素:" + node.Value);
- Console.Read();
- }
- }
- }
五、有序列表
SortedList采用键-值对存储,键不能重复,并且会根据key进行排序
- [Serializable]
- [DebuggerTypeProxy(typeof(System_DictionaryDebugView<,>))]
- [DebuggerDisplay("Count = {Count}")]
- [ComVisible(false)]
- public class SortedList<TKey, TValue> : IDictionary<TKey, TValue>, ICollection<KeyValuePair<TKey, TValue>>, IEnumerable<KeyValuePair<TKey, TValue>>, IDictionary, ICollection, IEnumerable
可以看出SortedList不仅具有字典的特性,还有集合,迭代的功能
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- //Key必须唯一,如果不唯一可以考虑Lookup<TKey,TElement>
- SortedList<int, String> sList = new SortedList<int, string>();
- sList.Add(100, "张三");
- sList.Add(21, "李四");
- sList.Add(13, "王五");
- sList.Add(44, "田六");
- sList.Add(35, "赵七");
- foreach (KeyValuePair<int, String> item in sList)
- {
- Console.WriteLine("key=" + item.Key.ToString() + ";value=" + item.Value);
- }
- Console.Read();
- }
- }
- }
六、字典
字典是很复杂的数据结构,允许通过key来查找值,字典可以自由添加、删除元素,没有集合由于移动元素导致的开销。
- [Serializable]
- [DebuggerTypeProxy(typeof(Mscorlib_DictionaryDebugView<,>))]
- [DebuggerDisplay("Count = {Count}")]
- [ComVisible(false)]
- public class Dictionary<TKey, TValue> : IDictionary<TKey, TValue>, ICollection<KeyValuePair<TKey, TValue>>, IEnumerable<KeyValuePair<TKey, TValue>>, IDictionary, ICollection, IEnumerable, ISerializable, IDeserializationCallback
可以看出字典也具有集合的特性,可以迭代
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- //Key必须唯一
- Dictionary<int, String> dict = new Dictionary<int, string>();
- dict.Add(11, "张三");
- dict.Add(1, "李四");
- dict.Add(2, "王五");
- dict.Add(16, "田六");
- dict.Add(12, "赵七");
- foreach (KeyValuePair<int, String> item in dict)
- {
- Console.WriteLine("key=" + item.Key.ToString() + ";value=" + item.Value);
- }
- Console.Read();
- }
- }
- }
说到字典,顺便谈一下有序字典,与有序列表对应;SortedDictionary,SortedList,SortedSet
会根据Key进行排序
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- //Key必须唯一
- SortedDictionary<int, String> dict = new SortedDictionary<int, string>();
- dict.Add(11, "张三");
- dict.Add(1, "李四");
- dict.Add(2, "王五");
- dict.Add(16, "田六");
- dict.Add(12, "赵七");
- foreach (KeyValuePair<int, String> item in dict)
- {
- Console.WriteLine("key=" + item.Key.ToString() + ";value=" + item.Value);
- }
- Console.Read();
- }
- }
- }
七、集
集(Set):包含不重复元素,常用HashSet,SortedSet
- [Serializable]
- [DebuggerDisplay("Count = {Count}")]
- [DebuggerTypeProxy(typeof(HashSetDebugView<>))]
- public class HashSet<T> : ISerializable, IDeserializationCallback, ISet<T>, ICollection<T>, IEnumerable<T>, IEnumerable
- [Serializable]
- [DebuggerTypeProxy(typeof(SortedSetDebugView<>))]
- [DebuggerDisplay("Count = {Count}")]
- public class SortedSet<T> : ISet<T>, ICollection<T>, IEnumerable<T>, ICollection, IEnumerable, ISerializable, IDeserializationCallback
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- HashSet<String> hSet = new HashSet<string>();
- hSet.Add("张三");
- hSet.Add("李四");
- hSet.Add("王五");
- hSet.Add("田六");
- hSet.Add("赵七");
- foreach (String item in hSet)
- {
- Console.WriteLine("foreach迭代:" + item);
- }
- Console.Read();
- }
- }
- }
- using System;
- using System.Collections.Generic;
- namespace ConsoleApplication1
- {
- public class Program
- {
- static void Main(string[] args)
- {
- SortedSet<String> hSet = new SortedSet<string>();
- hSet.Add("张三");
- hSet.Add("李四");
- hSet.Add("王五");
- hSet.Add("田六");
- hSet.Add("赵七");
- foreach (String item in hSet)
- {
- Console.WriteLine("foreach迭代:" + item);
- }
- Console.Read();
- }
- }
- }
性能比较:
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