What is the fastest way to build text?

Question

I have a large text (1000 lines) with formatting. Briefly (not this text but I will use an example) I have 2 ways to build it:

StringBuilder sb = new StringBuilder();
    sb.append("oi" +
    "meu nome" +
    "é" +
    "Jonny");

Or

    sb.append("oi");
    sb.append("meu nome");
    sb.append("é");
    sb.append("Jonny");

at runtime and memory, which would be the most appropriate? Or the two run at the same speed?

I’m using the visual studio 2017.

Answer 1

The first undoubtedly because it in practice is the same as

sb.append("oimeu nomeéJonny");

If it’s with variables it’s the same as:

sb.append(string.Concat(v1, v2, v3, v4));

I put in the Github for future reference.

The second is 4 isolated operations. therefore it costs more expensive. Of course there will be gain in a large operation, but the gain will be greater if you can avoid some of these operations. There will be gain if you can give a size at least approximate to the string final, even if it is a little exaggerated can compensate quite.

If you’re only gonna do four appends doesn’t pay to use the StringBuilder, it serves for a large amount of inclusions and either in a loop or similar mechanism. If it is without a loop in general it pays more to use a Concat(), Join(), Format() or even interpolation.

For this specific example, if you have nothing else you should do the simplest, it will be the fastest too. If it is only that it would be too absurd to use the first one. The second one would only be absurd.

see more in:

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• Why should I use the Stringbuilder class instead of the String class?
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• Performance: string "concatenated" or all in the same line?

It doesn’t matter if you’re using Visual Studio 2017, This has nothing to do with the IDE.