How to delete elements from golang array

In the Go language, you can use the Slice feature to implement the deletion operation of array elements. Deletion method: 1. Use append() to delete, the syntax is "append(list[:delete index], list[(delete index 1):]...)"; 2. Use copy() to delete, the syntax is "list [:copy(list, list[index:])]"; 3. Use len() to delete, the syntax is "list[:len(list)-N]".

The operating environment of this tutorial: Windows 7 system, GO version 1.18, Dell G3 computer.

In the Go language, you can use the Slice feature to implement the deletion operation of array elements. A slice is a reference to a contiguous fragment of an array, so a slice is a reference type (so more similar to the array type in C/C, or the list type in Python). This fragment can be the entire array, or it can It is a subset of some items identified by the start and end indexes. It should be noted that the items identified by the end index are not included in the slice.

Go language uses slices to delete array elements

Go language does not provide special syntax or interface for deleting slice elements, you need to use the slice itself To delete elements, there are three situations according to the position of the element to be deleted, namely deleting from the beginning, deleting from the middle and deleting from the tail. Among them, deleting elements at the end of the slice is the fastest. [Related recommendations: Go video tutorial, Programming teaching]

Delete from the beginning

You can delete the elements at the beginning Move the data pointer directly:

a = []int{1, 2, 3}
a = a[1:] // 删除开头1个元素
a = a[N:] // 删除开头N个元素

You can also move the data pointer without moving it, but to move the subsequent data to the beginning, you can use append to complete it in place (the so-called completion in place refers to the memory interval corresponding to the original slice data) Completed within, will not cause changes in the memory space structure):

a = []int{1, 2, 3}
a = append(a[:0], a[1:]...) // 删除开头1个元素
a = append(a[:0], a[N:]...) // 删除开头N个元素

You can also use the copy() function to delete the beginning elements:

a = []int{1, 2, 3}
a = a[:copy(a, a[1:])] // 删除开头1个元素
a = a[:copy(a, a[N:])] // 删除开头N个元素

Delete from the middle position

To delete the middle element, you need to move the remaining elements as a whole. You can also use append or copy to complete it in place:

a = []int{1, 2, 3, ...}
a = append(a[:i], a[i+1:]...) // 删除中间1个元素
a = append(a[:i], a[i+N:]...) // 删除中间N个元素
a = a[:i+copy(a[i:], a[i+1:])] // 删除中间1个元素
a = a[:i+copy(a[i:], a[i+N:])] // 删除中间N个元素

Delete from the tail

a = []int{1, 2, 3}
a = a[:len(a)-1] // 删除尾部1个元素
a = a[:len(a)-N] // 删除尾部N个元素

Deleting the beginning elements and deleting the tail elements can be considered as special cases of deleting the middle elements. Let’s look at an example below.

Array deletion example

[Example] Delete the element at the specified position of the slice.

package main

import "fmt"

func main() {
    seq := []string{"a", "b", "c", "d", "e"}

    // 指定删除位置
    index := 2

    // 查看删除位置之前的元素和之后的元素
    fmt.Println(seq[:index], seq[index+1:])

    // 将删除点前后的元素连接起来
    seq = append(seq[:index], seq[index+1:]...)

    fmt.Println(seq)
}

Code output result:

The code description is as follows:

• Line 1, declares an integer Slice, holds a string containing from a to e.

• Line 4, for the convenience of demonstration and explanation, use the index variable to save the position of the element that needs to be deleted.

• Line 7, seq[:index] represents the first half of the deleted element, the value is [1 2], seq[index 1:] represents the deleted element The second half of , the value is [4 5].

• Line 10, use the append() function to connect the two slices.

• Line 12 outputs the connected new slice. At this time, the element with index 2 has been deleted.

The code deletion process can be described using the following figure.

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