How to modify the value of a slice in golang

In the Go language, slicing is a commonly used data structure, which can easily handle dynamic length arrays. In some scenarios, we may need to modify the value of one or some elements in the slice. This article will introduce how to modify the value of the slice in the Go language.

The slice in Go language is a reference type, which contains a pointer to the underlying array, the length and capacity of the slice. Therefore, we can access elements in the slice via subscripts and modify them. For example, the following code demonstrates how to modify the value of a specified subscript in a slice:

package main

import "fmt"

func main() {
   // 定义一个切片
   s := []int{1, 2, 3, 4, 5}

   // 修改第3个元素的值
   s[2] = 100

   // 打印切片的值
   fmt.Println(s) // 输出：[1 2 100 4 5]
}

In the above code, we first define a slice s, and then pass s[ 2]Accessed the 3rd element in the slice and modified it to 100. Finally, we print out the modified value of slice s.

In addition to the above method, we can also loop through the slice and modify the value of each element one by one. For example, the following code demonstrates how to loop through a slice and modify all even elements in it to odd numbers.

package main

import "fmt"

func main() {
   // 定义一个切片
   s := []int{1, 2, 3, 4, 5}

   // 遍历切片，将所有偶数修改为奇数
   for i := 0; i < len(s); i++ {
      if s[i] % 2 == 0 {
         s[i] += 1
      }
   }

   // 打印切片的值
   fmt.Println(s) // 输出：[1 3 3 5 5]
}

In the above code, we first define a slice s, and then loop through each of its elements. If the value of the element is an even number, add 1 to it and change into an odd number. Finally, we print out the modified value of slice s.

In addition to the above method, we can also use the built-in function copy to modify the value of the slice. copyThe function can copy the contents of one slice to another slice and return the number of copied elements. If the length of the target slice is smaller than the length of the source slice, only the elements of the target slice length will be copied; if the length of the target slice is greater than the length of the source slice, after copying the elements of the source slice, the remaining target slice elements will remain unchanged. . For example, the following code demonstrates how to use the copy function to copy some elements of one slice to another slice.

package main

import "fmt"

func main() {
   // 定义一个切片
   s1 := []int{1, 2, 3, 4, 5}

   // 定义另一个切片，并复制s1中的部分元素到其中
   s2 := make([]int, 3, 5)
   copy(s2, s1[2:5])

   // 修改s2中的元素值
   for i, v := range s2{
      s2[i] = v * 10
   }

   // 打印切片的值
   fmt.Println(s1) // 输出：[1 2 3 4 5]
   fmt.Println(s2) // 输出：[30 40 50]
}

In the above code, we first define a slice s1, and then obtain s1 through s1[2:5] Copy the elements with subscripts from 2 to 4 to another slice s2. Next, we loop through s2 and multiply all element values ​​in it by 10. Finally, we print out the values ​​​​of s1 and s2. We can see that s1 has not been modified, and the element value in s2 All have become 10 times their original size.

To summarize, we can modify slices in the Go language through subscripts, loops and copy functions. In specific applications, you can choose the appropriate method to modify the value of the slice according to different scenarios.

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