.Net 3.5环境下常用数组性能测试

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时间: 2008-03-20 11:20

这件事情似乎很无聊，但是没人做，我来做下苦力吧。

以下是一些简单的测试。单位以ms计算。注意里面用到循环的数量有些事1W，有些是100W。

这些记录可以作为编程过程中的一些参考。

测试平台：

奔腾1.6G 双核CPU
1G内存
vs2008 调试环境测试。

一、ArrayList (100W,1W)
Stopwatch timer =
new Stopwatch();
timer.Start();

System.Collections.ArrayList al =
new System.Collections.ArrayList();

for (int i =
0; i <
1000000; i++)
{
al.Add(i);
}

timer.Stop();

Console.Write(timer.ElapsedMilliseconds.ToString() +
"\t");

Stopwatch timer1 =
new Stopwatch();
timer1.Start();

for (int i =
0; i <
10000; i++)
{
al.Contains(i);
}

timer1.Stop();

Console.WriteLine(timer1.ElapsedMilliseconds.ToString());

98 775
160 891
107 773
193 769

二、Hashtable (100W,1W)

Stopwatch timer =
new Stopwatch();
timer.Start();

System.Collections.Hashtable ht =
new System.Collections.Hashtable();

for (int i =
0; i <
1000000; i++)
{
ht.Add(i, i);
}

timer.Stop();

Console.Write(timer.ElapsedMilliseconds.ToString() +
"\t");

Stopwatch timer1 =
new Stopwatch();
timer1.Start();

for (int i =
0; i <
10000; i++)
{
ht.ContainsKey(i);
}

timer1.Stop();

Console.WriteLine(timer1.ElapsedMilliseconds.ToString());
}

375 0
673 0
540 0
495 0

把timer1提高到100万(Hashtable (100W,100W))

389 139
616 277
516 140
610 277

三、HashSet (100W,100W)

Stopwatch timer =
new Stopwatch();
timer.Start();

System.Collections.Generic.HashSet<int> ht =
new System.Collections.Generic.HashSet<int>();

for (int i =
0; i <
1000000; i++)
{
ht.Add(i);
}

timer.Stop();

Console.Write(timer.ElapsedMilliseconds.ToString() +
"\t");

Stopwatch timer1 =
new Stopwatch();
timer1.Start();

for (int i =
0; i <
1000000; i++)
{
ht.Contains(i);
}

timer1.Stop();

Console.WriteLine(timer1.ElapsedMilliseconds.ToString());

89 32
79 32
79 32
117 31

四、List (100W,1W)

Stopwatch timer =
new Stopwatch();
timer.Start();

System.Collections.Generic.List<int> ht =
new System.Collections.Generic.List<int>();

for (int i =
0; i <
1000000; i++)
{
ht.Add(i);
}

timer.Stop();

Console.Write(timer.ElapsedMilliseconds.ToString() +
"\t");

Stopwatch timer1 =
new Stopwatch();
timer1.Start();

for (int i =
0; i <
10000; i++)
{
ht.Contains(i);
}

timer1.Stop();

Console.WriteLine(timer1.ElapsedMilliseconds.ToString());

16 379
19 392
18 403
18 392

把List<int>换成List<object>

96 945
157 1033
106 909
193 910

换成string,i.ToString()

496 1238
531 1190
572 1246
536 1258

五、Dictionary (100W,100W)

Stopwatch timer =
new Stopwatch();
timer.Start();

System.Collections.Generic.Dictionary<int, int> ht =
new System.Collections.Generic.Dictionary<int, int>();

for (int i =
0; i <
1000000; i++)
{
ht.Add(i, i);
}

timer.Stop();

Console.Write(timer.ElapsedMilliseconds.ToString() +
"\t");

Stopwatch timer1 =
new Stopwatch();
timer1.Start();

for (int i =
0; i <
1000000; i++)
{
ht.ContainsKey(i);
}

timer1.Stop();

Console.WriteLine(timer1.ElapsedMilliseconds.ToString());

113 35
125 34
124 34
126 34

六、Dictionary Linq查询 (100W,100W)

用个Linq试试
Stopwatch timer =
new Stopwatch();
timer.Start();

System.Collections.Generic.Dictionary<int, int> ht =
new System.Collections.Generic.Dictionary<int, int>();

for (int i =
0; i <
1000000; i++)
{
ht.Add(i, i);
}

timer.Stop();

Console.Write(timer.ElapsedMilliseconds.ToString() +
"\t");

Stopwatch timer1 =
new Stopwatch();
timer1.Start();

for (int i =
0; i <
1000000; i++)
{
ht.Where(c => c.Key == i);
}

timer1.Stop();

Console.WriteLine(timer1.ElapsedMilliseconds.ToString());

112 177
107 78
125 70
107 82

结论：
1、如果是使用缓存的话，那么3.5带来的单泛型集合的HashSet可以替代List了。虽然载入速度慢一点，但是查询速度要比List泛型快很多。要注意到，上述测试List的查询时万级的，而HashSet是百万级

2、Dictionary泛型可以替换掉Hashtable了，虽然如果在字符或者object类型下可能会没这么明显。但是在数字类型的匹配上，Dictionary比Hashtable大概快了2倍，而这个开销估计是Hashtable的装箱造成的。

3、Linq还是要慢一些。

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