Detailed explanation of how to delete array elements in Go language

In Go language, array is an important data type. Like arrays in other languages, it is a set of data of the same type, and elements in the array can be accessed through an index. In some cases, we need to delete elements from an array. This article will introduce how to delete elements from an array in Go language.

If we want to delete an element in the array, Go language provides a built-in function append(). The function of this function is to add one or more elements to the end of the array to achieve the purpose of inserting elements. Therefore, deleting elements in an array usually requires a combination of append() and slicing.

We use the following example to demonstrate the specific method of array deletion:

//定义一个切片
package main

import "fmt"

func main() {
    a := []int{1, 2, 3, 4, 5}
    fmt.Println(a) //输出： [1 2 3 4 5]

    //删除a中的第三个元素（下标为2），并生成新的切片b
    b := append(a[:2], a[3:]...)
    fmt.Println(b) //输出： [1 2 4 5]

}

In the above code, we first define a slice a, and then use The append() function deletes the third element in a and generates a new slice b. Specifically, we first use slicing to intercept the element a[:2] before the third element (subscript 2) in a, and then ## The elements after the third element in #a a[3:] are spliced ​​together, and finally the ... operator is used to convert it into a list of variable parameters , passed to the append() function. append()The function will return a new slice b in which the third element has been deleted.

It should be noted that since the underlying layer of the slice is an array, you need to pay attention to the capacity and length of the array when operating on the slice. Normally, when we use the

append() function, if the length of the slice is less than or equal to its capacity, the function will directly append the elements to the back of the original array. But if the length is greater than the capacity, this function will create a new array to accommodate more elements. Therefore, in order to avoid unnecessary memory allocation, we should try to control the capacity of the slice and avoid frequent memory allocation.

In addition to the

append() function, the Go language also provides other methods to implement array deletion. For example, we can use the copy() function to copy part of a slice to another slice to achieve the effect of deleting elements. The following is a sample code:

package main

import "fmt"

func main() {
    a := []int{1, 2, 3, 4, 5}
    fmt.Println(a) //输出： [1 2 3 4 5]

    //删除a中的第三个元素（下标为2），并生成新的切片b
    b := make([]int, len(a)-1)
    copy(b, a[:2])
    copy(b[2:], a[3:])
    fmt.Println(b) //输出： [1 2 4 5]
}

In this example, we first create a new slice

b through the make() function, the length of the slice is the original array minus 1 from the length. Then, we use the copy() function to copy the part before and after the third element in a to the corresponding positions in b, to achieve For the purpose of deleting an element. Finally, we output b to the console to check whether the elements in the array were successfully deleted.

To sum up, array deletion in Go language can be achieved by combining

append() and slicing. In addition, you can also use the copy() function to achieve similar effects. No matter which method is used, you need to pay attention to memory allocation and the capacity and length of the array when operating to avoid unnecessary waste of resources.

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