C # performance analysis of three methods for determining null strings]

Performance analysis of three methods for determining null strings in C #

Author: qingyueer

Home page:Http://blog.csdn.net/21aspnet/Time: 2007.4.28

The three methods are as follows:
String A = "";
1. if (a = "")
2. If (A = string. Empty)
3. If (A. Length = 0)

The three methods are equivalent,Which method has the highest performance? I will illustrate the problem with an experiment.

Create three aspx pages (why use web pages, mainly using Microsoft Application Center test)

Webform1.aspx
Private void page_load (Object sender, system. eventargs E)
{
String A = "";
For (INT I = 0; I <= 1000000; I ++)
{
If (A = "")
{
}
}
}

Webform2.aspx
Private void page_load (Object sender, system. eventargs E)
{
String A = "";
For (INT I = 0; I <= 1000000; I ++)
{
If (A = string. Empty)
{

}
}
}

Webform3.aspx
Private void page_load (Object sender, system. eventargs E)
{
String A = "";
For (INT I = 0; I <= 1000000; I ++)
{
If (A. Length = 0)
{
}
}
}

Create three stress testing projects under Microsoft Application Center test:

Test results:

Webform1.aspx ---------- if (a = "")

Webform2.aspx ------- if (a = string. Empty)

Webform3.aspx ------- if (A. Length = 0)

Therefore, the result of quantification in the three methods is 98,105,168:

Method	Result
If (A = "")	98
If (A = string. Empty)	105
If (A. Length = 0)	168

So why is if (A. Length = 0) the fastest?
Because integer judgment is the fastest, there is no complicated process such as instantiation.

Therefore, we recommend that you use if (A. Length = 0) to determine whether the string is null ).