to lower case

leetcode地址

func toLowerCase(str string) string {
    nbs := make([]byte, len([]byte(str)))
    for i, v := range []byte(str) {
        nv := v
        if v >= 65 && v <= 90 {
            nv = v + 32
        }
        nbs[i] = nv
    }
    return string(nbs)
}