How to append a slice in Golang?

In Go, slices are dynamically-sized, flexible views into the elements of an array. Appending elements to a slice is a common operation that allows for the expansion of the slice as needed. The built-in append function is used to add elements to the end of a slice.In this article,we will learn How to Append a Slice in Golang.

Example

 package main 
import "fmt"

func main() {
 // Initial slice
 numbers := []int{1, 2, 3}
 fmt.Println("Original slice:", numbers)

 // Appending elements
 numbers = append(numbers, 4, 5, 6)
 fmt.Println("After appending:", numbers)
}

Syntax of append

The append function has the following syntax:

slice = append(slice, elements...)

Where:

• slice is the original slice to which elements are being added.
• elements are the values being appended. The ... operator is used to append multiple elements.

Appending Multiple Elements

You can append multiple elements to a slice at once using the append function.

Example

Original slice: [a b]
After appending: [a b c d]

Appending Another Slice

You are allowed to append one slice to another with the help of the ... operator. This allows for a seamless combination of slices.

Example

S1: [1 2 3]
S2: [4 5 6]
After appending S2 to S1: [1 2 3 4 5 6]

Understanding Capacity and Growth

When appending to a slice, if the length of the slice exceeds its capacity, Go automatically allocates a new underlying array to accommodate the additional elements.

Example

Initial slice capacity: 3
After initial append, capacity: 3
After exceeding capacity, capacity: 6