golang slice usage

Golang is a widely used programming language, and its simplicity and efficiency have attracted more and more developers. The Slice type is also one of the commonly used data structures in Golang. It not only supports dynamic growth, but also implements slicing operations. This article will introduce the use of Slice in detail.

1. What is Slice?

In Golang, Slice can be understood as a dynamic array. Compared with static arrays, Slice is more flexible and can automatically expand and reduce capacity, eliminating restrictions on capacity size and greatly improving the flexibility and reusability of code.

A Slice contains three important elements, namely the underlying array pointer, length and capacity. The length represents the number of elements stored in the Slice, and the capacity represents the maximum number of elements that the Slice can store.

2. Creation and initialization of Slice

In Golang, you can create and initialize it through the make function or directly use the Slice literal.

1. Create Slice through the make function.

The make function has three parameters, namely Slice type, length and capacity. Among them, the length must be specified, but the capacity is optional. When the capacity is not specified, the capacity defaults to the same as the length.

Sample code:

s := make([]int, 5)      // 创建一个初始值为 0，长度为 5，容量为 5 的 Slice
s := make([]int, 5, 10)  // 创建一个初始值为 0，长度为 5，容量为 10 的 Slice

2. Use Slice literal to create Slice.

Slice literals are enclosed by a pair of square brackets, with commas separating each value.

Sample code:

s := []int{1, 2, 3, 4, 5} // 创建一个包含 1，2，3，4，5 的 Slice

3. Slice operations

1. Slice access and modification.

Like arrays, you can use subscripts to access elements in Slice.

Sample code:

s := []int{1, 2, 3, 4, 5}
fmt.Println(s[0])  // 打印 Slice 中的第一个元素

Slice supports modification operations, but it should be noted that modifications to Slice will affect the underlying array and other Slices that reference the underlying array.

Sample code:

s := []int{1, 2, 3, 4, 5}
s[0] = 6 // 将 Slice 中的第一个元素修改为 6

2. Addition and deletion of Slice.

To append elements to Slice, you can use the built-in function append. This function will return a new Slice, leaving the original Slice unchanged.

Sample code:

s := []int{1, 2, 3, 4, 5}
s = append(s, 6) // 在 Slice 中追加一个元素 6

Deleting an element from Slice is also implemented through the append function. You need to use the slicing operation to exclude the element to be deleted.

Sample code:

s := []int{1, 2, 3, 4, 5}
s = append(s[:2], s[3:]...) // 删除 Slice 中的第三个元素，这里使用了切片操作

3. Slice’s slicing operation.

Like arrays, Slice also supports slicing operations. Slicing refers to "cutting" the original Slice, intercepting a part of the continuous elements, and obtaining a new Slice.

The syntax of the slice operation is slice[low:high], where slice represents the Slice to be sliced, low and high represent the position of the slice, but does not include the element of high.

Sample code:

s := []int{1, 2, 3, 4, 5}
slice := s[1:3] // 返回 [2, 3]

4. Expansion and reduction of Slice

When using Slice, the capacity of the underlying array will affect its efficiency and performance. When the Slice capacity is insufficient, it needs to be expanded; when the capacity is too large, it can be reduced to save memory space.

The process of expansion is that when the capacity of Slice is insufficient, a new underlying array will be created, with the length and capacity usually being twice the original, and then all the elements in the original Slice will be copied to the new array.

Sample code:

s := make([]int, 5, 10)
s = append(s, 6) // 在 Slice 中追加一个元素 6

The reduction process is to use the slicing operation to specify the length of the underlying array to be the same as the Slice length, thereby reducing the capacity.

Sample code:

s := []int{1, 2, 3, 4, 5}
s = s[:3] // 缩减 Slice 的容量为 3

5. Summary

This article introduces in detail the creation, initialization, access, modification, append, delete, slicing, expansion and reduction of Slice in Golang Wait for operations. Mastering the use of Slice can greatly improve the flexibility and efficiency of code, and help develop high-quality Golang front-end, back-end and mobile applications. I hope that through the introduction of this article, readers will have a deeper understanding and application of the Slice type in Golang.

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