To add to the other answers, most array list implementations reserve extra capacity at the end of the list so that new elements can be added to the end of the list in O(1) time. When the capacity of an array list is exceeded, a new, larger array is allocated internally, and all the old elements are copied over. Usually, the new array is double the size of the old one. This means that on average, adding new elements to the end of an array list is an O(1) operation in these implementations. So even if you don't know the number of elements in advance, an array list may still be faster than a linked list for adding elements, as long as you are adding them at the end. Obviously, inserting new elements at arbitrary locations in an array list is still an O(n) operation.

访问数组列表中的元素也比访问链表快，即使访问是顺序的。这是因为数组元素存储在连续的内存中，可以很容易地缓存。链表节点可能分散在许多不同的页面上。

如果知道要在任意位置插入或删除项，我建议只使用链表。数组列表在其他方面会更快。

这完全取决于你在迭代时所做的操作类型，所有数据结构都在时间和内存之间进行权衡，我们应该根据需要选择正确的DS。有些情况下，LinkedList比数组快，反之亦然。考虑数据结构上的三个基本操作。

搜索

由于array是基于索引的数据结构，搜索array.get(index)将花费O(1)时间，而linkedlist不是索引DS，因此您将需要遍历到index，其中index <=n, n是链表的大小，因此array在随机访问元素时比链表更快。

那么，这背后有什么好处呢?

As Arrays are contiguous memory blocks, large chunks of them will be loaded into the cache upon first access this makes it comparatively quick to access remaining elements of the array,as much as we access the elements in array locality of reference also increases thus less catch misses, Cache locality refers to the operations being in the cache and thus execute much faster as compared to in memory,basically In array we maximize the chances of sequential element access being in the cache. While Linked lists aren't necessarily in contiguous blocks of memory, there's no guarantee that items which appear sequentially in the list are actually arranged near each-other in memory, this means fewer cache hits e.g. more cache misses because we need to read from memory for every access of linked list element which increases the time it takes to access them and degraded performance so if we are doing more random access operation aka searching , array will be fast as explained below.

插入

这是简单和快速的LinkedList的插入是O(1)操作在LinkedList (Java)阵列相比,考虑数组充满的情况下,我们需要将内容复制到新数组如果数组完全使一个元素插入ArrayList O (n)在坏的情况下,而ArrayList还需要更新其指数年底如果你插入一些除了数组,链表的我们不必调整它,你只需要更新指针。

删除

它的工作原理类似于插入，在LinkedList中比在array中更好。

我做了一些基准测试，发现list类实际上比LinkedList随机插入更快:

using System;
using System.Collections.Generic;
using System.Diagnostics;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int count = 20000;
            Random rand = new Random(12345);

            Stopwatch watch = Stopwatch.StartNew();
            LinkedList<int> ll = new LinkedList<int>();
            ll.AddLast(0);
            for (int i = 1; i < count; i++)
            {
                ll.AddBefore(ll.Find(rand.Next(i)),i);

            }
            Console.WriteLine("LinkedList/Random Add: {0}ms", watch.ElapsedMilliseconds);

            watch = Stopwatch.StartNew();
            List<int> list = new List<int>();
            list.Add(0);
            for (int i = 1; i < count; i++)
            {
                list.Insert(list.IndexOf(rand.Next(i)), i);

            }
            Console.WriteLine("List/Random Add: {0}ms", watch.ElapsedMilliseconds);

            Console.ReadLine();
        }
    }
}

链表需要900毫秒，列表类需要100毫秒。

它创建后续整数的列表。每个新的整数被插入到一个已经在列表中的随机数之后。 也许List类使用了比数组更好的东西。

如果您需要在中间插入项，并且不想开始调整数组大小和移动内容，则列表的优势就会显现出来。

你是对的，通常情况下并非如此。我遇到过一些非常具体的案例，但不是很多。

数组具有O(1)随机访问，但是向数组中添加或删除内容的代价非常高。

链表在任何地方添加或删除项目和迭代都非常便宜，但随机访问是O(n)。

1)如上所述，与ArrayList(O(n))相比，在LinkedList中插入和删除操作具有良好的性能(O(1))。因此，如果应用程序需要频繁的添加和删除，那么LinkedList是最好的选择。

2)搜索(get方法)操作在Arraylist (O(1))中是快速的，但在LinkedList (O(n))中不是，所以如果有更少的添加和删除操作和更多的搜索操作要求，Arraylist将是你最好的选择。