“String.Equals(string)”和“==”那个快？

要比较两个字符串是否相等，有两种方法：

string toBeTested = "67412";

bool result;

result = toBeTested.Equals("67413");

和

result = toBeTested == "67413";

哪一种方法好呢？

测试程序：

int times = 100000000;

int start, end;

int i;

bool result;

string toBeTested = "67412";

start = System.Environment.TickCount;

for(i=0; i<times; i++)

{

result = toBeTested.Equals("67412");

}

end = System.Environment.TickCount;

Console.WriteLine("Equals True Time: " + (end-start)/1000.0 + " Seconds");

start = System.Environment.TickCount;

for(i=0; i<times; i++)

{

result = toBeTested == "67412";

}

end = System.Environment.TickCount;

Console.WriteLine("== True Time: " + (end-start)/1000.0 + " Seconds");

start = System.Environment.TickCount;

for(i=0; i<times; i++)

{

result = toBeTested.Equals("67413");

}

end = System.Environment.TickCount;

Console.WriteLine("Equals False Time: " + (end-start)/1000.0 + " Seconds");

start = System.Environment.TickCount;

for(i=0; i<times; i++)

{

result = toBeTested == "67413";

}

end = System.Environment.TickCount;

Console.WriteLine("== False Time: " + (end-start)/1000.0 + " Seconds");

结果：

Equals True Time: 3.234 Seconds

== True Time: 0.562 Seconds

Equals False Time: 3.391 Seconds

== False Time: 3.891 Seconds

可见当结果为true时，==比Equals()快很多；当结果为false时，Equals()略快于==。

结论：如果要比较的字符串相同的多，就用==；要比较的字符串中不同的多，就用Equals()。