. NET Deep Learning Notes (2): Performance comparison and analysis of 4 methods for judging empty strings in C #

An article about the performance analysis of the method of string null judgement, the experimental results have been given by the author, the conclusion is to use. Length==0 judgment is the most efficient, but the end of the article only a word, feeling not enough detail, so I write this article, calculate a supplement and study it.

Hardware environment for program code execution:

Cpu	Intel T2300 1.66GHz
Memory	Kingston DDR2 667 1G
Hard disk	80G 5400 ext. 8m

Software Environment for testing:

OS	Windows XP Pro
Ide	VS 2008 RTM

The code for the test is as follows:

3 variables are defined, 4 methods are called, and the test time is recorded for 100w Times:

stopwatch SW = new Stopwatch ()//Instantiate an object, recording time


string sEmpty1 = string. empty;//instantiates 3 string objects, and assigns the following values. Comparison test
for air separation

string sEmpty2 = "";


string sEmpty3 = "Stringnotempty";


////////////////////////////////////////////////////test sempty1///////////////////////////


SW. Start ()//Begin recording


for (int i = 0; I <= 1000000; i++)


{


if (sempty1.length = 0)


{ }


}


SW. Stop ()//stops recording time


Console.WriteLine ("String. Empty Length = = 0 Time cost is {0} ", SW. Elapsedmilliseconds);


////////


SW. Reset ()//Reset counter is 0;


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (sEmpty1 = "")


{ }


}


SW. Stop ();


Console.WriteLine ("String. Empty = \ "\" "Time cost is {0}", SW. Elapsedmilliseconds);


////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (sEmpty1 = = string. Empty)


{ }


}


SW. Stop ();


Console.WriteLine ("String. Empty = = String. Empty time cost is {0} ", SW. Elapsedmilliseconds);


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (string. IsNullOrEmpty (sEmpty1))


{}


}


SW. Stop ();


Console.WriteLine ("String. IsNullOrEmpty time cost is {0} ", SW. Elapsedmilliseconds);


Console.WriteLine ();


////////////////////////////////////////////////////test sempty2///////////////////////////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (sempty2.length = 0)


{}


}


SW. Stop ();


Console.WriteLine ("\" \ "Length = = 0 Time") is {0} ", SW. Elapsedmilliseconds);


////////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (SEmpty2 = "")


{}


}


SW. Stop ();


Console.WriteLine ("\" \ = = \ "\" Time cost is {0} ", SW.) Elapsedmilliseconds);


/////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (SEmpty2 = = string. Empty)


{}


}


SW. Stop ();


Console.WriteLine ("\" = = string.) Empty Test3 time cost is {0} ", SW. Elapsedmilliseconds);


/////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (string. IsNullOrEmpty (sEmpty2))


{}


}


SW. Stop ();


Console.WriteLine ("\" \ "string.) IsNullOrEmpty time cost is {0} ", SW. Elapsedmilliseconds);


Console.WriteLine ();


////////////////////////////////////////////////////test sempty3///////////////////////////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (sempty3.length = 0)


{}


}


SW. Stop ();


Console.WriteLine ("\" stringnotempty\ "Length = = 0 Time cost is {0}", SW. Elapsedmilliseconds);


////////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (SEmpty3 = "")


{}


}


SW. Stop ();


Console.WriteLine ("\" stringnotempty\ "= = \" "Time cost is {0}", SW. Elapsedmilliseconds);


////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (sEmpty3 = = string. Empty)


{}


}


SW. Stop ();


Console.WriteLine ("\ stringnotempty\" = string. Empty Test3 time cost is {0} ", SW. Elapsedmilliseconds);


////


SW. Reset ();


SW. Start ();


for (int i = 0; I <= 1000000; i++)


{


if (string. IsNullOrEmpty (sEmpty3))


{}


}


SW. Stop ();


Console.WriteLine ("\" stringnotempty\ "IsNullOrEmpty time cost is {0}", SW. Elapsedmilliseconds);