Most efficient way to return string concatenation from property

Question

Ive read a few posts on here and the common suggestion is that stringbuilder is the most efficent if joining over three strings.

all variables are other properties.

public string Summary
{
  get 
  {
    return Name.Replace("_", " ") + "<strong>[" + Total + " Devices - " + BadCount + " Offline, " + PendingCount + " Pending]</strong>";
  }
}

Im joining four, is a simple concatenation suitable or should I ue stringbuilder? Just seems a little overkill.

You know you're actually concatenating 8 strings right? Every + is a concatenation. — Destrictor, Jan 24 '13 at 09:41
Can you provide a link for your assertion that the efficiency minimum for a StringBuilder is 3 strings? — slugster, Jan 24 '13 at 09:42
Doesn't the C# compiler automatically convert `+` concatenations into `StringBuilder` calls (just like Java does)? — Sebastian Krysmanski, Jan 24 '13 at 09:53
Jon Skeet: [Concatenating Strings Efficiently](http://www.yoda.arachsys.com/csharp/stringbuilder.html) — slugster, Jan 24 '13 at 10:02
possible duplicate of [What's the best string concatenation method using C#?](http://stackoverflow.com/questions/21078/whats-the-best-string-concatenation-method-using-c) — slugster, Jan 24 '13 at 10:04
http://stackoverflow.com/questions/21078/whats-the-best-string-concatenation-method-using-c -- Sorry cant find original post, but checkign others the numbers vary widely. — DavidB, Jan 24 '13 at 10:59
You know you're actually concatenating 8 strings right? -- Of course, silly me. — DavidB, Jan 24 '13 at 11:03

Tim Schmelter · Accepted Answer · 2013-01-24T09:53:55.593

8

Use whatever is most readable in this case. Otherwise it's premature optimization.

I would use String.Format:

String result = String.Format("{0}<strong>[{1} Devices - {2} Offline, {3} Pending]</strong>"
, Name.Replace("_", " ")
, Total
, BadCount
, PendingCount);
return result;

Even string concatenation is not that bad since strings are stored in the intern pool. So if you use a string a second time it's not created but the already available reference is used.

So as rule of thumb:

If you're concatenating few strings and the code gets hardly to understand, use String.Format
If you're concatenating few (literal) strings and the code is still readable, use +(string concatenation)
If you're creating strings in a (long) loop with variable strings, use a StringBuilder

edited Jan 24 '13 at 09:53

answered Jan 24 '13 at 09:43

Tim Schmelter

450,073
74
686
939

3

Reminds me of this quote: 'You should be more worried about the maintainability and readability of your code than its performance.' The performance difference will be nearly non-existent in the example. – BBQ Jan 24 '13 at 09:53
Thanks for the answer, Ill use string format and accept your answer for the additonal info. – DavidB Jan 24 '13 at 11:04

score 2 · Answer 2 · answered Jan 24 '13 at 09:42

2

Use String.Format

public string Summary
{
  get 
  {
    return String.Format(
        "{0}<strong>[{1} Devices - {2} Offline, {3} Pending </strong>",
        Name.Replace("_", " "), Total, BadCount, PendingCount);
  }
}

answered Jan 24 '13 at 09:42

Mehmet Ataş

11,081
6
51
78

4

Why? Apart from tidiness, what performance advantage does it offer over concatenation? (Note this is not disputing your answer, you simply need to do better than say *"use string.Format()"*). – slugster Jan 24 '13 at 09:44
String.Format uses a `StringBuilder`. It might be neater, but I doubt it's faster. – Tim M. Jan 24 '13 at 09:45
2

Far and away the best approach. String.Format() is optimised, and it also allows you to easily provide localization by putting the format string into the resources. You should always do that anyways, even if you're not going to be localising stuff. – Matthew Watson Jan 24 '13 at 09:45
Excellent answer, this is the approach I will use. – DavidB Jan 24 '13 at 11:03

Most efficient way to return string concatenation from property

2 Answers2