{"id":161,"date":"2024-09-10T11:04:25","date_gmt":"2024-09-10T04:04:25","guid":{"rendered":"https:\/\/gotutorial.org\/?page_id=161"},"modified":"2024-09-25T20:18:51","modified_gmt":"2024-09-25T13:18:51","slug":"go-arrays","status":"publish","type":"page","link":"https:\/\/www.gotutorial.org\/go-tutorial\/go-arrays\/","title":{"rendered":"Go Arrays"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn how to use the Go arrays to store a fixed number of elements of the same type.<\/p>\n\n\n\n

In Go, arrays are a basic data structure for storing a fixed number of elements with the same types. For example, you can use arrays to store a list of numbers or strings.<\/p>\n\n\n\n

Declaration<\/h2>\n\n\n\n

To declare an array, you specify the size and the type of element as follows:<\/p>\n\n\n

var<\/span> arrayName [size] type<\/span><\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
For example, the following declares an array of five integers:<\/p>\n\n\n
var<\/span> scores [5<\/span>] int<\/span><\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
This declaration creates an array of 5 integers. Since the default values of integers are zero, the scores array holds five numbers zero.<\/p>\n\n\n\n
Initialization<\/h2>\n\n\n\n
Like other variables, Go allows you to initialize an array at the time of declaration. For example:<\/p>\n\n\n
var<\/span> scores [5<\/span>] int<\/span> = [5<\/span>] int<\/span> {1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, we initialize elements of the scores array from 1 to 5.<\/p>\n\n\n\n
Alternatively, you can use the short variable declaration:<\/p>\n\n\n
scores := [5<\/span>] int<\/span> { 1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Go can infer the length of the array based on the initial values, you can omit the size in the initialization like this:<\/p>\n\n\n
scores := [...] int<\/span> { 1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span> }<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Accessing elements<\/h2>\n\n\n\n
Go is zero-based indexing. It means that the first element of the array has an index of zero, the second element has an index of 1, and so on.<\/p>\n\n\n\n
To access an element, you can use the index notation:<\/p>\n\n\n
arrayName[index]<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
For example, the following displays the first element of the scores array to the console:<\/p>\n\n\n
package<\/span> main\n\nimport<\/span> \"fmt\"<\/span>\n\nfunc<\/span> main<\/span>()<\/span><\/span> {\n    scores := [...] int<\/span> {1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}\n    fmt.Println(scores[0<\/span>])\n}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
1<\/span><\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Modifying elements<\/h2>\n\n\n\n
To modify an element, you also use the index notation and assign a new value to the element:<\/p>\n\n\n
arrayName[index] = newValue<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
For example, the following changes the first element of the scores array to 0:<\/p>\n\n\n
package<\/span> main\n\nimport<\/span> \"fmt\"<\/span>\n\nfunc<\/span> main<\/span>()<\/span><\/span> {\n    scores := [...]int<\/span>{1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}\n    scores[0<\/span>] = 0<\/span>\n    fmt.Println(scores[0<\/span>])\n}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
0<\/span><\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Getting the length of an array<\/h2>\n\n\n\n
To get the length of an array, you can use the len()<\/code> function:<\/p>\n\n\n
len<\/span>(arrayName)<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
For example:<\/p>\n\n\n
package<\/span> main\n\nimport<\/span> \"fmt\"<\/span>\n\nfunc<\/span> main<\/span>()<\/span><\/span> {\n    scores := [...] int<\/span> {1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}\n    len<\/span> := len<\/span>(scores)\n    fmt.Println(len<\/span>)\n}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
5<\/span><\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, we get the length of the scores array using the len()<\/code> function and display it on the screen.<\/p>\n\n\n\n
Iterating over array elements<\/h2>\n\n\n\n
To iterate over array elements, you can use a for loop. Here’s a simple for loop that iterates over the elements of the scores array and displays each element on the screen:<\/p>\n\n\n
package<\/span> main\n\nimport<\/span> \"fmt\"<\/span>\n\nfunc<\/span> main<\/span>()<\/span><\/span> {\n    scores := [...] int<\/span> {1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}\n    for<\/span> i := 0<\/span>; i < len<\/span>(scores); i++ {\n        fmt.Println(scores[i])\n    }\n}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
1<\/span>\n2<\/span>\n3<\/span>\n4<\/span>\n5<\/span><\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
In practice, you often use the for range to iterate elements of an array:<\/p>\n\n\n
package<\/span> main\n\nimport<\/span> \"fmt\"<\/span>\n\nfunc<\/span> main<\/span>()<\/span><\/span> {\n    scores := [...] int<\/span> {1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}\n    for<\/span> index, value := range<\/span> scores {\n        fmt.Println(index, value)\n    }\n}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
The for range<\/a> loop allows you to access index and value which is\u00a0more readable than the traditional for loop.<\/p>\n\n\n\n
Slicing<\/h2>\n\n\n\n
Go allows you to slice an array to create a slice. Slices are a more flexible data structure in Go. Slices are like arrays but have dynamic sizes. It means that the size of the slices can grow and shrink dynamically.<\/p>\n\n\n\n
To create a slice from an array, you use the following syntax:<\/p>\n\n\n
array[start:end]<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
In this syntax:<\/p>\n\n\n\n
    \n
  • start<\/code> is the starting index (inclusive).<\/li>\n\n\n\n
  • end<\/code> is the ending index (exclusive).<\/li>\n<\/ul>\n\n\n\n
    The slice will contain the elements from the start<\/code> to the end - 1<\/code>.<\/p>\n\n\n\n
    For example, the following creates a slice that contains the elements 1, 2, and 3:<\/p>\n\n\n
    package<\/span> main\n\nimport<\/span> \"fmt\"<\/span>\n\nfunc<\/span> main<\/span>()<\/span><\/span> {\n    scores := [...]int<\/span>{1<\/span>, 2<\/span>, 3<\/span>, 4<\/span>, 5<\/span>}\n    slices := scores[1<\/span>:4<\/span>]\n    fmt.Println(slices)\n}<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
    Output:<\/p>\n\n\n
    [2<\/span> 3<\/span> 4<\/span>]<\/code><\/span>Code language:<\/span> Go<\/span> (<\/span>go<\/span>)<\/span><\/small><\/pre>\n\n\n
    Summary<\/h2>\n\n\n\n
      \n
    • Arrays are fixed-length sequences of elements with the same types.<\/li>\n\n\n\n
    • Arrays are zero-based indexing.<\/li>\n\n\n\n
    • Use array[index]<\/code> to access an element of the array at the index.<\/li>\n\n\n\n
    • Use for<\/code> and for range<\/code> loops to iterate over elements.<\/li>\n\n\n\n
    • Use the len()<\/code> function to get the length of an array.<\/li>\n\n\n\n
    • Slices are like arrays but have a dynamic length.<\/li>\n\n\n\n
    • Use slicing to create a slice from an array.<\/li>\n<\/ul>\n
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