How to create a sub-slice from an existing slice in Golang?

To create a sub-slice from an existing slice in Golang, you can use the slice indexing notation slice[start:end].

Here's an example of creating a sub-slice from an existing slice in Golang:

package main

import "fmt"

func main() {
    // Creating the existing slice
    numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

    // Creating a sub-slice using the existing slice
    subSlice := numbers[2:6]

    fmt.Println(subSlice) // Output: [3 4 5 6]
}

In this example, an existing slice numbers is created. We then create a sub-slice subSlice by using the indexing notation numbers[2:6]. This creates a new sub-slice that includes elements from the index 2 up to, but not including, the index 6 of the numbers slice.

Note that modifying the sub-slice will also modify the original slice as they share the same underlying array. If you want to create a completely separate copy of the sub-slice, you can use the copy function:

package main

import "fmt"

func main() {
    // Creating the existing slice
    numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

    // Creating a sub-slice using the existing slice
    subSlice := make([]int, 4)
    copy(subSlice, numbers[2:6])

    fmt.Println(subSlice) // Output: [3 4 5 6]

    // Modifying the sub-slice does not affect the original slice
    subSlice[0] = 999
    fmt.Println(subSlice) // Output: [999 4 5 6]
    fmt.Println(numbers)  // Output: [1 2 3 4 5 6 7 8 9 10]
}

In this modified example, we use the copy function to create a separate copy of the sub-slice. Modifying the copied sub-slice does not affect the original numbers slice.