2.30. Go language multidimensional array

Go language supports multi-dimensional arrays. The following are common declaration methods of multi-dimensional arrays:

var variable_name [SIZE1][SIZE2]...[SIZEN] variable_type

The following example declares a 3D array of integers:

var threedim [5][10][4]int

2.30.1. Two-dimensional array #

Two-dimensional array is the simplest multi-dimensional array, and two-dimensional array is essentially composed of one-dimensional array. A two-dimensional array is defined as follows:

var arrayName [ x ][ y ] variable_type

variable_type for Go data type of the language arrayName is the name of the array, the two-dimensional array can be thought of as a table, x is the row and y is the column. The following figure shows that a two-dimensional array a has three rows and four columns:

Elements in a two-dimensional array can be passed through the a[ i ][ j ] to visit.

Example #

package main
import "fmt"
func main() {
    // Step 1: Create an array
    values := [][]int{}
    // Step 2: Add two rows of one-dimensional arrays to
    an empty two-dimensional array using the append() function
    row1 := []int{1, 2, 3}
    row2 := []int{4, 5, 6}
    values = append(values, row1)
    values = append(values, row2)
    // Step 3: Display two rows of data
    fmt.Println("Row 1")
    fmt.Println(values[0])
    fmt.Println("Row 2")
    fmt.Println(values[1])
    // Step 4: Accessing the first element
    fmt.Println("The first element is：")
    fmt.Println(values[0][0])
}

The output of the above instance is as follows:

Row 1
[1 2 3]
Row 2
[4 5 6]
The first element is：
1

2.30.2. Initialize two-dimensional array #

Multidimensional arrays can be initialized by curly braces. The following example is a two-dimensional array of three rows and four columns:

a := [3][4]int{
 {0, 1, 2, 3} ,   /*  The first row index is 0 */
 {4, 5, 6, 7} ,   /*  The second row has an index of 1 */
 {8, 9, 10, 11},   /* The third row has an index of 2 */
}

Note: the penultimate line in the above code } , there must be a comma, because the last line } you can’t have a single line, but it can be written like this:

a := [3][4]int{
 {0, 1, 2, 3} ,   /*  The first row index is 0 */
 {4, 5, 6, 7} ,   /*  The second row has an index of 1 */
 {8, 9, 10, 11}}   /* The third row has an index of 2 */

The following example initializes a two-dimensional array of two rows and two columns:

Example #

package main
import "fmt"
func main() {
    // Create a 2D array
    sites := [2][2]string{}
    // Adding Elements to a 2D Array
    sites[0][0] = "Google"
    sites[0][1] = "Runoob"
    sites[1][0] = "Taobao"
    sites[1][1] = "Weibo"
    // Display Results
    fmt.Println(sites)
}

The output of the above instance is as follows:

[[Google Runoob] [Taobao Weibo]]

2.30.3. Access two-dimensional array #

A two-dimensional array is accessed by specifying coordinates. Such as row and column indexes in an array, for example:

val := a[2][3]
or
var value int = a[2][3]

The above example accesses the fourth element in the third row of the two-dimensional array val .

Two-dimensional arrays can use loop nesting to output elements:

Example #

package main
import "fmt"
func main() {
   /* Array -5 rows and 2 columns*/
   var a = [5][2]int{ {0,0}, {1,2}, {2,4}, {3,6},{4,8}}
   var i, j int
   /* Output array elements */
   for  i = 0; i < 5; i++ {
      for j = 0; j < 2; j++ {
         fmt.Printf("a[%d][%d] = %d\\n", i,j, a[i][j] )
      }
   }
}

The output of the above instance is as follows:

a[0][0] = 0
a[0][1] = 0
a[1][0] = 1
a[1][1] = 2
a[2][0] = 2
a[2][1] = 4
a[3][0] = 3
a[3][1] = 6
a[4][0] = 4
a[4][1] = 8

The following example creates a multi-dimensional array with a different number of elements in each dimension:

Example #

package main
import "fmt"
func main() {
    // Create an empty two-dimensional array
    animals := [][]string{}
    // Create a three-dimensional array with different lengths for each array
    row1 := []string{"fish", "shark", "eel"}
    row2 := []string{"bird"}
    row3 := []string{"lizard", "salamander"}
    // Add a one-dimensional array to a two-dimensional array using the
    append() function
    animals = append(animals, row1)
    animals = append(animals, row2)
    animals = append(animals, row3)
    // Loop output
    for i := range animals {
        fmt.Printf("Row: %v\\n", i)
        fmt.Println(animals[i])
    }
}

The output of the above instance is as follows:

Row: 0
[fish shark eel]
Row: 1
[bird]
Row: 2
[lizard salamander]