Avoid frequent splicing of strings and conversion types for performance improvements. 1. Use strings.Builder or pre-allocated byte slice instead = splicing; 2. Cache the conversion results of strings and byte slices or use a type to reduce the number of conversions; 3. Use byte slices when frequently modifying content; 4. Use strings.Contains, HasPrefix, HasSuffix and other optimization functions first when determining the existence of substrings. These methods can significantly improve processing efficiency and reduce memory overhead.

Operation optimization of string and byte slices in Go is actually quite common, especially when processing large amounts of text or network data. Although the two look similar, the underlying mechanisms are different, and the operation methods need to be paid attention to, otherwise it is easy to get stuck or write code with poor performance.

The following is a few common scenarios to talk about how to handle strings and byte slices more efficiently.

Avoid frequent splicing of strings

In Go, strings are immutable, and each splicing generates a new string object. If you use = splicing strings in a loop, the performance may be poor, especially when the data volume is large.

suggestion:

• If you want to splice multiple times, use strings.Builder first
• Or allocate a byte slice with sufficient capacity in advance and then convert it to string

for example:

 var b strings.Builder
for i := 0; i < 1000; i {
    b.WriteString("some string")
}
result := b.String()

This method is much faster than = it directly, and has less memory allocation.

Be careful with memory allocation when converting strings and byte slices

In some scenarios, we need to convert the string into a byte slice (such as encryption, network transmission), or vice versa. The conversion between these two types will trigger a memory copy. Although it is not particularly slow, it will still affect performance if it is called frequently.

suggestion:

• If you just read the content, try to avoid repeated conversions
• If conversion is necessary, cache results can be considered to reduce duplicate overhead

For example:

 s := "hello"
b := []byte(s) // There is a copy here

The same goes for the other way around:

 b := []byte("world")
s = string(b) // Copy again

If you need to convert frequently, it is best to use one of the types uniformly to reduce the number of conversions.

Using byte slice to process variable content is more efficient

When you need to modify the content frequently, the string is not suitable. At this time, you should use []byte .

For example, if you want to replace a certain character or modify it in place, it will be much more convenient to use byte slice:

 data := []byte("hello world")
data[6] = 'W' // Change to "hello World"

If you use strings, you have to constantly create new objects, which is much less efficient.

In addition, some standard library functions also accept []byte parameters, such as bytes.TrimSpace() , bytes.Split() , etc., which are suitable for high-performance processing.

Try to use the functions in the strings package to determine the existence of substrings.

Some people like to use strings.Contains() , while others write loops to determine whether there is a certain substring, which is actually unnecessary.

Go's strings package has been optimized a lot, and functions such as Contains , HasPrefix , and HasSuffix are all very fast, so it is recommended to use them first.

for example:

 if strings.Contains(s, "target") {
    // do something
}

Unless you have very special needs, don’t implement the search logic yourself, as errors are prone to may not be faster.

Basically these more practical techniques. Go is designed in this regard quite concisely. As long as you pay attention to not redirecting the types randomly and do not abuse string splicing, you will generally not encounter too many performance problems.

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