2.29. Go language array

2.29.1. Declare array #

Go language array declaration needs to specify the element type and the number of elements. The syntax format is as follows:

var variable_name [SIZE] variable_type 

The above is how one-dimensional arrays are defined. For example, the following defines an array balance , the length is 10 and the type is float32 :

var balance [10] float32 

2.29.2. Initialize array #

The following demonstrates array initialization:

var balance = [5]float32{1000.0, 2.0, 3.4, 7.0, 50.0} 

We can also quickly initialize the array while declaring it literally:

balance := [5]float32{1000.0, 2.0, 3.4, 7.0, 50.0} 

If the length of the array is uncertain, you can use the ... instead of the length of the array, the compiler deduces the length of the array based on the number of elements:

var balance = [...]float32{1000.0, 2.0, 3.4, 7.0, 50.0} or balance := [...]float32{1000.0, 2.0, 3.4, 7.0, 50.0} 

If the length of the array is set, we can also initialize the element by specifying the subscript:

// Initialize elements with indexes 1 and 3 balance := [5]float32{1:2.0,3:7.0} 

Initialize the array {} number of elements in cannot be greater than [] number in.

If you ignore [] number in does not set the size of the array Go language sets the size of the array based on the number of elements:

balance[4] = 50.0 

The above example reads the fifth element. Array elements can be read (or modified) by index (position), which starts at 0, the first element index is0, the second index is 1, and so on.

2.29.3. Access array elements #

Array elements can be read by index (position). The format is the array namefollowed by parentheses, and the value of the index is in the brackets. Forexample:

var salary float32 = balance[9] 

The above example reads the array balance value of the 10th element.

The following shows an example of a complete operation of an array (declaration, assignment, access):

package main import "fmt" func main() { var n [10]int /* n is an array with a length of 10 */ var i,j int /* Initialize elements for array n */ for i = 0; i < 10; i++ { n[i] = i + 100 /* Set element to i + 100 */ } /* Output the value of each array element */ for j = 0; j < 10; j++ { fmt.Printf("Element[%d] = %d\\n", j, n[j] ) } } 

Element[0] = 100 Element[1] = 101 Element[2] = 102 Element[3] = 103 Element[4] = 104 Element[5] = 105 Element[6] = 106 Element[7] = 107 Element[8] = 108 Element[9] = 109 

package main import "fmt" func main() { var i,j,k int // Quickly initialize an array while declaring it balance := [5]float32{1000.0, 2.0, 3.4, 7.0, 50.0} /* Output array elements */ ... for i = 0; i < 5; i++ { fmt.Printf("balance[%d] = %f\\n", i, balance[i] ) } balance2 := [...]float32{1000.0, 2.0, 3.4, 7.0, 50.0} /* Output the value of each array element */ for j = 0; j < 5; j++ { fmt.Printf("balance2[%d] = %f\\n", j, balance2[j] ) } // Initialize elements with indexes 1 and 3 balance3 := [5]float32{1:2.0,3:7.0} for k = 0; k < 5; k++ { fmt.Printf("balance3[%d] = %f\\n", k, balance3[k] ) } } 

balance[0] = 1000.000000 balance[1] = 2.000000 balance[2] = 3.400000 balance[3] = 7.000000 balance[4] = 50.000000 balance2[0] = 1000.000000 balance2[1] = 2.000000 balance2[2] = 3.400000 balance2[3] = 7.000000 balance2[4] = 50.000000 balance3[0] = 0.000000 balance3[1] = 2.000000 balance3[2] = 0.000000 balance3[3] = 7.000000 balance3[4] = 0.000000 

2.29.4. More content #

Array pair Go language is very important, and we will introduce more about the array below: