Unity C#for和foreach效率比较

比较结果如下

测试比较的代码如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class TimeDuiBi : MonoBehaviour
{
    List<int> list = new List<int>();

    private void Start()
    {
        for (int i = 0; i < 3000000; i++)
        {
            list.Add(i);
        }    
    }
    private void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
        {
            System.Diagnostics.Stopwatch stopwatch = new System.Diagnostics.Stopwatch();
            stopwatch.Start();
            int temp1 = 0;
            int cout = list.Count;
            for (int i = 0; i < cout; i++)
            {
                temp1 += list[i];
            }
            stopwatch.Stop();
            Debug.Log("for time=: " + stopwatch.Elapsed.TotalMilliseconds + "temp1:" + temp1);


            System.Diagnostics.Stopwatch stopwatch2 = new System.Diagnostics.Stopwatch();
            stopwatch2.Start();
            int temp3 = 0;
            for (int i = 0; i < list.Count; i++)
            {
                temp3 += list[i];
            }
            stopwatch2.Stop();
            Debug.Log("for list.Count  time=: " + stopwatch2.Elapsed.TotalMilliseconds + "temp3:" + temp3);


            System.Diagnostics.Stopwatch stopwatch1 = new System.Diagnostics.Stopwatch();
            stopwatch1.Start();
            int temp2 = 0;
            foreach (var item in list)
            {
                temp2 += item;
            }
            stopwatch1.Stop();
            Debug.Log("foreach time=: " + stopwatch1.Elapsed.TotalMilliseconds + "temp2:" + temp2);
        }
    }
}

最后可以自行运行测试