Comparison of the implementation method and difference between golang string splicing

Interview questions:

Performance optimization
How to optimize memory allocation in the following code?

func concat(strs []string) string {
    var s string
    for _, str := range strs {
        s += str
    }
    return s
}

Examination points: immutability of string splicing, pre-allocated memory.

How to optimize objects created at high frequency?
Inspection points: life cycle management of object pools and reduce GC pressure.

answer:

In Go, there are many ways to implement string splicing, each of which has its advantages and disadvantages. Here are some common methods and their characteristics:

1. Use+Operator

s1 := "Hello"
s2 := "World"
result := s1 + " " + s2

advantage:

Simple and intuitive, suitable for splicing of small strings.

shortcoming:

Each splicing generates new strings, resulting in additional memory allocation and copying, with poor performance, especially when there are a large number of splicing.

2. Use

s1 := "Hello"
s2 := "World"
result := ("%s %s", s1, s2)

advantage:

Supports formatting and is suitable for string stitching that needs to be formatted.

shortcoming:

Poor performance because it involves formatting and is suitable for small amounts of splicing.

3. Use

s := []string{"Hello", "World"}
result := (s, " ")

advantage:

Efficient, suitable for slicing string slices, especially when large numbers of strings.

shortcoming:

You need to put the string into the slice first, which is suitable for scenarios where all strings are known.

4. Use

var buffer 
("Hello")
(" ")
("World")
result := ()

advantage:

Efficient, suitable for frequent splicing and less memory allocation.

shortcoming:

The code is slightly lengthy.

5. Use（Go 1.10+）

var builder 
("Hello")
(" ")
("World")
result := ()

advantage:

Efficient, suitable for frequent splicing, less memory allocation,More efficient.

shortcoming:

Only available for Go 1.10 and above.

6. Use[]byteandappend

var b []byte
b = append(b, "Hello"...)
b = append(b, " "...)
b = append(b, "World"...)
result := string(b)

advantage:

Efficient, suitable for frequent splicing and less memory allocation.

shortcoming:

The code is a bit complicated.

Summarize

• A small amount of splicing:use+or, simple and intuitive.
• A large number of splicing:use、or, better performance.
• Frequent splicing:recommend, best performance.

Choosing the right method can improve code performance and readability.

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