Hi, everyone!

Do you have any use cases to manipulate large strings? Have you ever wondered about optimizing your code? Let's explore the difference between the native string and the string builder. When should we use string builder? When could we use string manipulation directly? My premise is we should use the string builder when we have large string manipulation, and we can use string manipulation directly if we combine two or three strings.

Speed/Performance and Memory

I ran the Benchmark using .NET 8 and BenchmarkDotNet. The result may vary depending on your machine. My machine specs:

1. Intel Core i7-9750H CPU @ 2.60GHz, 6 Core(s), 12 Logical Processor(s)
2. RAM 32 GB, 2667 MHz

The Result

This is the raw result after running my Benchmark. I will explain case by case.

Append Case

As you can see, the String Builder always wins. It's not only in terms of performance but also allocated memory. The ratio of performance and memory is high. You know, it's a big deal!

If you wonder why the string concat uses large memory when looping, it will copy the string N times. The string is immutable, so they need to copy the content.

Append String Builder

Append String

Prepend Case

As you can see, the String Builder starts struggling after dealing with prepend. I will choose String Builder if I have memory concerns. Of course, there is a tread-off. I rarely do prepend the string. If needed to do so, I might choose a different approach.

If you need to learn more about the difference between String and String Builder, please visit this documentation.

Prepend String Builder

Prepend String

Benchmark Code

Thank you

Do you have any feedback? Feel free to drop your comment. Thank you for reading. :)