split and merge []byte in go

chunk_split.go

package main

import (
	"fmt"
)

func main() {
	s := "He turned in the research paper on Friday; otherwise, he would have not passed the class."
	fmt.Printf("%s\nlenght:%d\n", s, len(s))

	chunked := chunk([]byte(s), 3)
	fmt.Printf("%s\nlenght:%d\n", chunked, len(chunked))

	merged := merge(chunked)
	fmt.Printf("%s\nlenght:%d\n", merged, len(merged))
}

func chunk(b []byte, size int) (bb [][]byte) {
	for len(b) > 0 {
		if len(b) < size {
			size = len(b)
		}
		bb, b = append(bb, b[:size]), b[size:]
	}
	return
}

func merge(bb [][]byte) (b []byte) {
	switch len(bb) {
	case 0:
	case 1:
		return bb[0]
	default:
		for i := range bb {
			b = append(b, bb[i]...)
		}
	}
	return
}

https://play.golang.org/p/XnRN91uavnE