Go Arrays
Fixed-size collections of elements in Go
📊 What are Go Arrays?
Arrays in Go are fixed-size collections that store elements of the same type. They provide a way to group related data together with a predetermined length that cannot be changed.
// Declare and initialize an array
var numbers [5]int = [5]int{1, 2, 3, 4, 5}
fmt.Println(numbers) // Output: [1 2 3 4 5]
Output:
[1 2 3 4 5]
Key Array Concepts
Fixed Size
Arrays have a fixed length set at declaration
var arr [3]string // Size is 3Zero-Indexed
Array elements start from index 0
arr[0] = "first" // First element
arr[1] = "second" // Second elementSame Type
All elements must be the same data type
var ages [4]int // Only integers
var names [3]string // Only stringsFast Access
Direct access to elements by index
value := arr[2] // Get third element🔹 Array Declaration
There are several ways to declare and initialize arrays in Go:
// Method 1: Declare then assign
var fruits [3]string
fruits[0] = "apple"
fruits[1] = "banana"
fruits[2] = "orange"
// Method 2: Declare and initialize
var colors [3]string = [3]string{"red", "green", "blue"}
// Method 3: Short declaration
numbers := [4]int{10, 20, 30, 40}
// Method 4: Let Go count the elements
scores := [...]int{95, 87, 92, 78, 85}Output:
fruits: [apple banana orange]
colors: [red green blue]
numbers: [10 20 30 40]
scores: [95 87 92 78 85]
🔹 Accessing Array Elements
Use square brackets with the index to access or modify elements:
package main
import "fmt"
func main() {
// Create an array
grades := [5]int{85, 92, 78, 96, 88}
// Access elements
fmt.Println("First grade:", grades[0])
fmt.Println("Last grade:", grades[4])
// Modify an element
grades[2] = 82
fmt.Println("Updated grades:", grades)
// Get array length
fmt.Println("Number of grades:", len(grades))
}Output:
First grade: 85
Last grade: 88
Updated grades: [85 92 82 96 88]
Number of grades: 5
🔹 Looping Through Arrays
Use for loops to iterate through array elements:
package main
import "fmt"
func main() {
cities := [4]string{"New York", "London", "Tokyo", "Paris"}
// Method 1: Traditional for loop
fmt.Println("Method 1:")
for i := 0; i < len(cities); i++ {
fmt.Printf("City %d: %s\n", i+1, cities[i])
}
// Method 2: Range loop
fmt.Println("\nMethod 2:")
for index, city := range cities {
fmt.Printf("Index %d: %s\n", index, city)
}
// Method 3: Range loop (values only)
fmt.Println("\nMethod 3:")
for _, city := range cities {
fmt.Println("City:", city)
}
}Output:
Method 1:
City 1: New York
City 2: London
City 3: Tokyo
City 4: Paris
Method 2:
Index 0: New York
Index 1: London
Index 2: Tokyo
Index 3: Paris
Method 3:
City: New York
City: London
City: Tokyo
City: Paris