What are slices in Golang? Detailed analysis

Title: In-depth exploration of slice types in Golang

Golang is a programming language developed by Google and has been highly sought after by developers since its inception. In Golang, slice is a very important and commonly used data structure, which can provide efficient data processing and management methods in many scenarios. This article will delve into the slice types in Golang, including the definition, operation and underlying implementation principles of slices, and deepen understanding through detailed code examples.

1. The definition and basic concepts of slicing

In Golang, slicing is a lightweight encapsulation of an array. It has the characteristics of dynamic growth and can dynamically adjust the length as needed. A slice contains three elements: a pointer to the underlying array, the length of the slice, and the capacity of the slice.

// 创建一个切片
var slice1 []int

// 使用make函数创建具有初始长度和容量的切片
slice2 := make([]int, 3, 5)

// 初始化切片并赋值
slice3 := []int{1, 2, 3, 4, 5}

In the code example above, we showed several ways to create slices in different ways. It should be noted that slicing is a reference to the original array, and operations on slicing will affect the contents of the original array.

2. Slicing operations

2.1 Adding elements to the slice

You can add elements to the slice through the append function. If the addition of new elements causes the underlying array to be not long enough, then It will be automatically expanded.

s := []int{1, 2, 3}
s = append(s, 4)
fmt.Println(s) // [1 2 3 4]

2.2 Interception of slices

The subsequence of the slice can be intercepted through the slice expression, including the start index and the end index.

s := []int{1, 2, 3, 4, 5}
s1 := s[1:3]
fmt.Println(s1) // [2 3]

2.3 Slice copy

Use the copy function to copy the data of one slice to another slice.

s1 := []int{1, 2, 3}
s2 := make([]int, len(s1))
copy(s2, s1)
fmt.Println(s2) // [1 2 3]

3. The underlying implementation principle of slicing

The bottom layer of a slice is represented by a structure:

type slice struct {
    array unsafe.Pointer // 指向底层数组的指针
    len   int            // 切片的长度
    cap   int            // 切片的容量
}

The essence of a slice is a structure, where array is a pointer to the bottom layer The pointer of the array, len represents the length of the slice, and cap represents the capacity of the slice. When a slice is expanded, the underlying array is reallocated and the original data is copied to the new array.

Conclusion

Through this article’s in-depth discussion of slice types in Golang, we understand the definition, operation and underlying implementation principles of slices. As an important data structure in Golang, slicing can help developers process data and manage memory more efficiently. An in-depth understanding of slice types is of great significance to improving the level of Golang development. I hope this article is helpful to readers, thank you!

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