[Author: @mdimamhosen Date: 2025-04-19 Category: interview-qa/slices Tags: [go, slices, arrays, make]

Slices

Slices are also used to store multiple values of the same type in a single variable, however unlike arrays, the length of a slice can grow and shrink as you see fit.

There are several ways to create a slice 👇

1. Using the []datatype{values} format
2. Create a slice from an array
3. Using the make() function

// name := []datatype{values}
// name := []int{}
package main
import ("fmt")

func main() {
  myslice1 := []int{}
  fmt.Println(len(myslice1))
  fmt.Println(cap(myslice1))
  fmt.Println(myslice1)

  myslice2 := []string{"Go", "Slices", "Are", "Powerful"}
  fmt.Println(len(myslice2))
  fmt.Println(cap(myslice2))
  fmt.Println(myslice2)
}

Make() Method

The make function will create a zeroed array and return a slice referencing an array. This is a great way to create a dynamically sized array. To create a slice using the make function, we need to specify three arguments: type, length, and capacity.

package main
import "fmt"

func main() {
    slice := make([]string, 3, 5)
    fmt.Println("Length", len(slice))
    fmt.Println("Capacity", cap(slice))
    fmt.Println(slice)
}

Frequently Asked Questions

1. How do you create an empty slice in Go?

Answer: Use []datatype{} to create an empty slice.

package main
import "fmt"

func main() {
    myslice := []int{}
    fmt.Println("Empty Slice:", myslice) // []
}

2. How do you create a slice with initial values?

Answer: Use []datatype{values}.

package main
import "fmt"

func main() {
    myslice := []int{1, 2, 3}
    fmt.Println("Slice with Values:", myslice) // [1 2 3]
}

3. How do you create a slice from an array?

Answer: Use slicing syntax array[start:end].

package main
import "fmt"

func main() {
    arr := [5]int{1, 2, 3, 4, 5}
    myslice := arr[1:4]
    fmt.Println("Slice from Array:", myslice) // [2 3 4]
}

4. How do you use the make function to create a slice?

Answer: Use make(type, length, capacity).

package main
import "fmt"

func main() {
    myslice := make([]int, 3, 5)
    fmt.Println("Slice with Make:", myslice) // [0 0 0]
}

5. How do you append elements to a slice?

Answer: Use the append function.

package main
import "fmt"

func main() {
    myslice := []int{1, 2, 3}
    myslice = append(myslice, 4, 5)
    fmt.Println("Appended Slice:", myslice) // [1 2 3 4 5]
}

6. How do you copy one slice to another?

Answer: Use the copy function.

package main
import "fmt"

func main() {
    src := []int{1, 2, 3}
    dest := make([]int, len(src))
    copy(dest, src)
    fmt.Println("Copied Slice:", dest) // [1 2 3]
}

7. How do you find the length and capacity of a slice?

Answer: Use len(slice) and cap(slice).

package main
import "fmt"

func main() {
    myslice := []int{1, 2, 3}
    fmt.Println("Length:", len(myslice)) // 3
    fmt.Println("Capacity:", cap(myslice)) // 3
}

8. How do you create a multidimensional slice?

Answer: Use slices of slices.

package main
import "fmt"

func main() {
    matrix := [][]int{
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9},
    }
    fmt.Println("Multidimensional Slice:", matrix)
}

9. How do you remove an element from a slice?

Answer: Use slicing to exclude the element.

package main
import "fmt"

func main() {
    myslice := []int{1, 2, 3, 4, 5}
    myslice = append(myslice[:2], myslice[3:]...)
    fmt.Println("Slice after Removal:", myslice) // [1 2 4 5]
}

10. How do you iterate over a slice in Go?

Answer: Use a for loop or range.

package main
import "fmt"

func main() {
    myslice := []int{1, 2, 3}
    for i, v := range myslice {
        fmt.Printf("Index: %d, Value: %d\n", i, v)
    }
}

⚡ Array vs Slice