Comments on: StringBuilder is not always faster – Part 1 of 2

By: Fixed: What's the best string concatenation method using C#? #answer #solution #it | IT Info

Sat, 07 Feb 2015 06:48:01 +0000

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By: How to: What's the best string concatenation method using C#? | SevenNet

How to: What's the best string concatenation method using C#? | SevenNet — Wed, 17 Dec 2014 01:27:22 +0000

[…] From Chinh Do – StringBuilder is not always faster: […]

By: Sam

Sam — Tue, 11 Dec 2012 09:07:22 +0000

Read this article which focuses on the ‘why’ aspect.

http://www.codetails.com/punitganshani/why-is-stringbuilder-faster-in-string-concatenations/20121030

By: Lelala

Lelala — Wed, 15 Aug 2012 13:13:45 +0000

In the end, it depends on the specific case.
In most cases, that little margin is only in theory relevant – and if that would be important to you, you may be better off with another language/framework.
For enterprise apps, maintainability and quality is much more important than the very last lightspeed seconds, i’d say.
Sure, some webpages may be experience an improvement in their html-output speed, but its always a trade off…

By: Trevor

Trevor — Wed, 08 Jul 2009 00:36:59 +0000

Use a MemoryProfiler to see which one is better

By: Chinh Do

Chinh Do — Fri, 24 Apr 2009 11:17:47 +0000

Marvin: Good question. Thanks. I am curious about it too so I decided to run some measurements again. My result indicates that doing the initialization like you suggested will save some time off of the StringBuilder result. However it was not enough to be faster than the string test. Seems like it would be a good idea to always seed the initial value as part of the construction if you can do it.

Chinh

By: Marvin

Marvin — Thu, 23 Apr 2009 05:38:39 +0000

‘###
This block of code took 1484 milliseconds to run on my PC:

for (int i = 0; i <= 1000000; i++)
{
// Concat strings 3 times using StringBuilder
StringBuilder s = new StringBuilder();
s.Append(i.ToString());
s.Append(i.ToString());
s.Append(i.ToString());
}

And this one, using traditional concatenation, took slightly less time (1344 milliseconds):

for (int i = 0; i <= 1000000; i++)
{
// Concat strings 3 times using traditional concatenation
string s = i.ToString();
s = s + i.ToString();
s = s + i.ToString();
}

The above data suggests that StringBuilder only starts to work faster once the number of concatenations exceed 3.
‘###

I noticed in the ‘string’ example you initialize s with the first string. Would StringBuilder be equivalent or faster for 3 concatenations if you initialized stringbuilder also with the first string? e.g. result in 3 lines instead of 4:

StringBuilder s = new StringBuilder(i.ToString(),16);
s.Append(i.ToString());
s.Append(i.ToString());

*Note StringBuilder Initializer includes default size of 16, otherwise it would be reallocating memory with each append since the size would also initialize to 1.

By: Chinh Do

Chinh Do — Mon, 20 Apr 2009 22:09:00 +0000

Michael: That makes a lot of sense. Thanks.

By: Michael

Michael — Mon, 20 Apr 2009 19:12:37 +0000

If .Net handles String and StringBuilder like Java does, the reason that 3 is the break even point has to do with object creation. With 3 concatenations, each method creates 5 objects (by my count).

StringBuilder:
1 StringBuilder
3 Strings for input
1 String for the final result

Concatenation:
3 Strings for input
1 String for the result of the concatenation of String 2 + 3
1 String for the result of the concatenation of String 1 and the above

By: 1kHz | anti-keseronokan » Blog Archive » String Concatenation dan Performance

Sun, 30 Sep 2007 03:26:07 +0000

[…] StringBuilder is not always faster StringBuilder is not always faster – Part 2 […]