Go has a built-in append function which add elements in the slice:
func append(slice []Type, elems …Type) []Type
But how if we want to the “prepend” effect? Maybe we should use copy function. E.g.:
package main
import "fmt"
func main() {
var s []int = []int{1, 2}
fmt.Println(s)
s1 := make([]int, len(s) + 1)
s1[0] = 0
copy(s1[1:], s)
s = s1
fmt.Println(s)
}
The result is like this:
[1 2]
[0 1 2]
But the above code looks ugly and cumbersome, so an elegant implementation maybe here:
s = append([]int{0}, s...)
BTW, I also have tried to write a “general-purpose” prepend:
func Prepend(v interface{}, slice []interface{}) []interface{}{
return append([]interface{}{v}, slice...)
}
But since []T can’t convert to an []interface{} directly (please refer https://golang.org/doc/faq#convert_slice_of_interface, it is just a toy, not useful.
Reference:
Go – append/prepend item into slice
https://github.com/NanXiao/golang-101-hacks