Tips and methods for clearing slices in golang

Go language is a very popular open source programming language, one of which is often used in daily development. It has great advantages in fields such as system programming and network programming. When we develop in Go language, one data type that needs to be processed frequently is slice.
Slice is the most widely used data structure in the Go language. It is more flexible and convenient than arrays. However, when we use slices, we will find that Slice will occupy a certain amount of memory when not in use. This We need to clean it up. So how to clear Slice? Next, let’s talk about the tips and methods of clearing slices.

First we need to understand the internal mechanism of Slice. They do this through arrays. The slice itself does not store data, it just represents a reference to a continuous array.
The built-in garbage collection in the Go language will traverse the memory blocks that have been allocated by the entire program, find out the active memory blocks, that is, the memory blocks in use, string them together with a linked list, and recycle all the rest.
So, we can assert that if we want to clear a slice, the remaining slice will be empty. Although the underlying memory block of the slice has not been cleared, Go's garbage collection mechanism will reclaim it and release the memory.
So, we concluded that the most reliable way to clear slice is to let slice point to a new empty slice.

The sample code is as follows:

package main

import "fmt"

func main() {
    var s []int
    s = append(s, 1, 2, 3) // 赋值一些元素

    fmt.Println("before clear:")
    fmt.Println(s)

    s = s[:0] // 清空slice

    fmt.Println("after clear:")
    fmt.Println(s)
}

In the above code, we first define an empty slice s. Then use the append operation to assign some elements to the slice. Finally, we use s = s[:0] to clear the slice and print the slice. We can see that the slice becomes an empty slice.

It should be noted that when using s[:0] to clear the slice, the original slice's underlying memory block is not cleared, but Go's garbage collection mechanism will recycle it and release the memory. This method is also very reliable for large-scale slice clearing, and is simple and easy to use.

In addition, if we want to clear the slice, we can also use the make operation to create a new empty slice, as shown below:

package main

import "fmt"

func main() {
    var s []int
    s = append(s, 1, 2, 3) // 赋值一些元素

    fmt.Println("before clear:")
    fmt.Println(s)

    s = make([]int, 0) // 清空slice

    fmt.Println("after clear:")
    fmt.Println(s)
}

In the above example, we also first define an empty slice s. Then use the append operation to assign some elements to the slice. Finally, we use make([]int, 0) to clear the slice and print the slice. You can see that the slice becomes an empty slice.

To sum up, we can clearly see that clearing slice can be done in a simple and easy way: s = s[:0] or s = make([]int, 0). Both methods are very convenient, can realize the function of clearing the slice, are highly reliable, and are easy to understand. Therefore, in daily development, we can use different methods to clear slices according to actual needs to improve the quality and efficiency of the code.

The above is the detailed content of Tips and methods for clearing slices in golang. For more information, please follow other related articles on the PHP Chinese website!