How to Efficiently Delete Elements from a Go Slice Using Append?

Deleting Elements in a Slice

The Go programming language provides a convenient way to delete elements from a slice using the append function. This technique involves constructing a new slice by combining certain segments of the original slice.

How it Works

Consider the following code snippet:

func main() {
    a := []string{"Hello1", "Hello2", "Hello3"}
    fmt.Println(a) // [Hello1 Hello2 Hello3]
    a = append(a[:0], a[1:]...)
    fmt.Println(a) // [Hello2 Hello3]
}

Step 1: Split the Slice

The first step is to split the slice into two segments:

• a[:0] represents an empty segment from the start of the slice up to the first element.
• a[1:] represents the remaining elements after the first element.

Step 2: Reconstruct the Slice

The append function is then used to construct a new slice by concatenating the two segments:

• append(a[:0], ...) takes the empty segment as the first argument and appends the remaining elements as variadic arguments.
• The ellipsis (...) in a[1:]... unpacks the slice into separate arguments.

Result

The resulting slice, stored in a, now contains the elements from position 1 onwards, effectively deleting the first element.

Variadic Arguments

Variadic arguments, denoted by ellipsis, are used in function definitions to accept an arbitrary number of arguments of the same type. When calling a function with variadic arguments, the ... operator unpacks a slice into individual arguments.

In this case, the variadic arguments unpack the slice a[1:] into individual strings.

By combining selective slicing and variadic arguments, this code trick provides a concise and efficient way to delete elements from a slice in Go.

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