Understanding Arrays and Slices in Go

Arrays and slices are fundamental data structures in the Go programming language for managing collections of elements.

An array in Go is a fixed-size sequence of elements of the same type. The size of an array is specified at compile time and cannot be changed at runtime. Arrays provide direct access to individual elements using zero-based indexing.

Slices, on the other hand, are dynamic and flexible wrappers around arrays. A slice is a lightweight data structure that represents a segment of an underlying array. Unlike arrays, slices can grow or shrink dynamically at runtime. Slices include a pointer to the underlying array, along with a length and capacity, allowing for efficient operations like appending elements.

Understanding the differences between arrays and slices is crucial for effective memory management and data manipulation in Go. Arrays are suitable for fixed-size collections, while slices are preferred for handling variable-size data and supporting dynamic operations. Both arrays and slices are integral to Go’s idiomatic approach to managing collections and data structures efficiently.

In an array, store zero or more than zero elements in it. which means the index of the first element is array [0] and the index of the last element is an array [len(array)-1].

Arrays are created in two different ways:

1. Using var keyword

1. Go program to illustrate how to create:
   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   package main

   import "fmt"

   func main() {

   var a [5]int

   fmt.Println(" size of the array: ", a)

   }

   package main import "fmt" func main() { var a [5]int fmt.Println(" size of the array: ", a) }

   package main
   import "fmt"
   
   func main() {
       var a [5]int
       fmt.Println(" size of the array: ", a)
   }
   

   Output :

   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   PS C:\GO_Language\Array> go run arr.go

   thr size of the array [0 0 0 0 0]

   PS C:\GO_Language\Array> go run arr.go thr size of the array [0 0 0 0 0]

   PS C:\GO_Language\Array> go run arr.go
   thr size of the array [0 0 0 0 0]
   

2. Go program to illustrate the values of an array
   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   package main

   import "fmt"

   func main() {

   a: = [5]int {1, 3, 4, 2, 5}

   sum: = 0

   for i: = 0; i < len(a); i++ {

   sum += a[i]

   fmt.Println("The value :", sum)

   }

   }

   package main import "fmt" func main() { a: = [5]int {1, 3, 4, 2, 5} sum: = 0 for i: = 0; i < len(a); i++ { sum += a[i] fmt.Println("The value :", sum) } }

   package main
   
   import "fmt"
   
   func main() {
       a: = [5]int {1, 3, 4, 2, 5}
       sum: = 0
       for i: = 0; i < len(a); i++ {
           sum += a[i]
           fmt.Println("The value :", sum)
       }
   }
   

   Output:

   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   PS C:\GO_Language\Array> go run arr2.go

   The value : 1

   The value : 4

   The value : 8

   The value : 10

   The value : 15

   PS C:\GO_Language\Array> go run arr2.go The value : 1 The value : 4 The value : 8 The value : 10 The value : 15

   PS C:\GO_Language\Array> go run arr2.go
   The value : 1
   The value : 4
   The value : 8
   The value : 10
   The value : 15
   

3. Go program to illustrate and insert the values in an array using for loop
   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   package main

   import "fmt"

   func main() {

   var n [10]int

   var i, j int

   for i = 0; i < 10; i++ {

   n[i] = i + 100

   }

   for j = 0; j < 10; j++ {

   fmt.Printf("Element[%d] =%d\n", j, n[j])

   }

   }

   package main import "fmt" func main() { var n [10]int var i, j int for i = 0; i < 10; i++ { n[i] = i + 100 } for j = 0; j < 10; j++ { fmt.Printf("Element[%d] =%d\n", j, n[j]) } }

   package main
   
   import "fmt"
   
   func main() {
       var n [10]int
       var i, j int
       for i = 0; i < 10; i++ {
           n[i] = i + 100
       }
       for j = 0; j < 10; j++ {
           fmt.Printf("Element[%d] =%d\n", j, n[j])
       }
   }
   

   Output :

   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   PS C:\GO_Language\Array> go run arr3.go

   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

   PS C:\GO_Language\Array> go run arr3.go 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

   PS C:\GO_Language\Array> go run arr3.go
   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
   

4. Go program to illustrate the Address of a variable
   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   package main

   import "fmt"

   func main() {

   x: = 7

   y: = &x

   fmt.Println(x, y)

   }

   package main import "fmt" func main() { x: = 7 y: = &x fmt.Println(x, y) }

   package main
   import "fmt"
   
   func main() {
       x: = 7
       y: = &x
       fmt.Println(x, y)
   
   }
   

   Output:

   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   PS C:\GO_Language\Array> go run arr4.go

   7 0xc000014088

   PS C:\GO_Language\Array> go run arr4.go 7 0xc000014088

   PS C:\GO_Language\Array> go run arr4.go
   7 0xc000014088
   

5. Go program to illustrate Assigning values through pointers
   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   package main

   import "fmt"

   func main() {

   i, j: = 42, 2372

   p: = &i

   fmt.Println(*p)

   *p = 21

   fmt.Println(i)

   p = &j

   *p = *p / 37

   fmt.Println(j)

   }

   package main import "fmt" func main() { i, j: = 42, 2372 p: = &i fmt.Println(*p) *p = 21 fmt.Println(i) p = &j *p = *p / 37 fmt.Println(j) }

   package main
   
   import "fmt"
   func main() {
       i, j: = 42, 2372
       p: = &i
       fmt.Println(*p)
       *p = 21
       fmt.Println(i)
       p = &j
       *p = *p / 37
       fmt.Println(j)
   
   }
   

   Output:

   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   PS C:\GO_Language\Array> go run arr5.go

   42

   21

   64

   PS C:\GO_Language\Array>

   PS C:\GO_Language\Array> go run arr5.go 42 21 64 PS C:\GO_Language\Array>

   PS C:\GO_Language\Array> go run arr5.go
   42
   21
   64
   PS C:\GO_Language\Array>
   

6. Go program to illustrate the value of null pointer.
   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   package main

   import "fmt"

   func main() {

   var ptr *int

   fmt.Printf("the Value of ptr is :%x\n", ptr)

   }

   package main import "fmt" func main() { var ptr *int fmt.Printf("the Value of ptr is :%x\n", ptr) }

   package main
   
   import "fmt"
   
   func main() {
       var ptr *int
       fmt.Printf("the Value of ptr is :%x\n", ptr)
   }
   

   Output :

   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   PS C:\GO_Language\Array> go run arr6.go

   the Value of ptr is :0

   PS C:\GO_Language\Array> go run arr6.go the Value of ptr is :0

   PS C:\GO_Language\Array> go run arr6.go
   the Value of ptr is :0
    
   

7. Go program to illustrate the division using pointer
   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   package main

   import "fmt"

   func main() {

   i, j: = 42, 2372

   p: = &i

   fmt.Println(*p)

   fmt.Printf("%T \n ", p)

   *p = 21

   fmt.Println(i)

   p = &j

   *p = *p / 37

   fmt.Println(j)

   }

   package main import "fmt" func main() { i, j: = 42, 2372 p: = &i fmt.Println(*p) fmt.Printf("%T \n ", p) *p = 21 fmt.Println(i) p = &j *p = *p / 37 fmt.Println(j) }

   package main
   
   import "fmt"
   
   func main() {
       i, j: = 42, 2372
       p: = &i
       fmt.Println(*p)
       fmt.Printf("%T \n ", p)
   
       *p = 21
       fmt.Println(i)
       p = &j
       *p = *p / 37
       fmt.Println(j)
   
   }
   

   Output :

   Plain text

   Copy to clipboard

   Open code in new window

   EnlighterJS 3 Syntax Highlighter

   PS C:\GO_Language\Array> go run arr7.go

   42

   *int

   21

   64

   PS C:\GO_Language\Array> go run arr7.go 42 *int 21 64

   PS C:\GO_Language\Array> go run arr7.go
   42
   *int 
    21
   64