golang slice delete an item

Preface

In Golang, slice is a dynamic array that can increase or decrease its length at will, which is very flexible. When using slice, sometimes you need to delete an item in a dynamic array to meet your own needs. This article will introduce how to implement the slice deletion operation through Golang's built-in functions and the method of creating new slices.

1. Implement slice deletion through built-in functions

In Golang’s built-in function library, there is a function called “append”, which can be used to dynamically expand the length of the slice and add it to the end of the slice. Add elements. Therefore, we can implement the slice deletion operation by using this function and combining it with subscripts. The specific steps are as follows:

1. Define a slice

Suppose we define an integer slice named "numbers":

numbers := []int{1, 2, 3, 4, 5}

2. Definition A subscript

According to the characteristics of slice, we can delete an element in it through a subscript. For example, if we want to delete the element with index 2 in slice (that is, the number 3), we can define a variable named "index" and assign it a value of 2:

index := 2

3. Use the append function Delete elements

Next, we can use the append function to splice the elements in the slice before index and the elements after index to achieve the deletion operation. The specific code is as follows:

numbers = append(numbers[:index], numbers[index+1:]...)

In this code, ":index" means intercepting from the starting position of the slice to the position with index-1 (that is, 0~1), "index 1:" means starting from The position with subscript index 1 is cut to the end of the slice (that is, 3~4). Use three dots "..." to concatenate two slices into a new slice.

The complete code is as follows:

package main

import (
    "fmt"
)

func main() {
    // 定义 slice
    numbers := []int{1, 2, 3, 4, 5}
    // 定义下标
    index := 2
    // 使用 append 函数删除元素
    numbers = append(numbers[:index], numbers[index+1:]...)
    fmt.Println(numbers)    // [1 2 4 5]
}

2. Implement slice deletion by creating a new slice

In addition to using the append function and subscript to achieve slice deletion, we can also use Create a new empty slice and add the elements you want to retain to it to get a new slice. The specific steps are as follows:

1. Define a slice

Also assume that we define an integer slice named "numbers":

numbers := []int{1, 2, 3, 4, 5}

2. Define a subscript

We still use subscripts to specify the elements to be deleted. Assuming that we still want to delete the element with index 2 (that is, the number 3), we can assign the index value to the "index" variable:

index := 2

3. Create an empty slice

Next, we can create a new empty slice with a length of 0 through the make function:

newNumbers := make([]int, 0)

4. Add the elements that need to be retained

Next, we can use for Loop and add the elements that need to be retained to the new slice:

for i := 0; i < len(numbers); i++ {
    if i != index {
        newNumbers = append(newNumbers, numbers[i])
    }
}

Among them, "if i != index" means that only elements other than the element with the subscript index are added to the new slice.

The complete code is as follows:

package main

import (
    "fmt"
)

func main() {
    // 定义 slice
    numbers := []int{1, 2, 3, 4, 5}
    // 定义下标
    index := 2
    // 新建一个空 slice
    newNumbers := make([]int, 0)
    // 添加需要保留的元素
    for i := 0; i < len(numbers); i++ {
        if i != index {
            newNumbers = append(newNumbers, numbers[i])
        }
    }
    fmt.Println(newNumbers)    // [1 2 4 5]
}

Summary

In Golang, we can implement the slice deletion operation through the built-in function append and create a new slice, which is simple, practical and Flexibility and changeability. Through the introduction of this article, I believe readers can already understand how to quickly and effectively implement slice deletion operations, which will be helpful in their own development work.

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