New Way:
From Go 1.10 there is a strings.Builder
type, please take a look at this answer for more detail.
Old Way:
Use the bytes
package. It has a Buffer
type which implements io.Writer
.
package main
import (
"bytes"
"fmt"
)
func main() {
var buffer bytes.Buffer
for i := 0; i < 1000; i++ {
buffer.WriteString("a")
}
fmt.Println(buffer.String())
}
This does it in O(n) time.