确保convert你的string成为一片符文:见“Slice string into letters”

a := []rune(s)
for i, r := range a {
    fmt.Printf("i%d r %c\n", i, r)
    // every 3 i, do something
}
a[n:n+3]
i

s := "世a界世bcd界efg世"

如果你试图逐字节地解析它,你会错过(在每3个字符实现中的一个天真的分裂)一些“索引模3”(等于2,5,8和11),因为索引将增加超过那些值:

for i, r := range s {
    res = res + string(r)
    fmt.Printf("i %d r %c\n", i, r)
    if i > 0 && (i+1)%3 == 0 {
        fmt.Printf("=>(%d) '%v'\n", i, res)
        res = ""
    }
}

输出:

i  0 r 世
i  3 r a   <== miss i==2
i  4 r 界
i  7 r 世  <== miss i==5
i 10 r b  <== miss i==8
i 11 r c  ===============> would print '世a界世bc', not exactly '3 chars'!
i 12 r d
i 13 r 界
i 16 r e  <== miss i==14
i 17 r f  ===============> would print 'd界ef'
i 18 r g
i 19 r 世 <== miss the rest of the string
a := []rune(s)
for i, r := range a {
    res = res + string(r)
    fmt.Printf("i%d r %c\n", i, r)
    if i > 0 && (i+1)%3 == 0 {
        fmt.Printf("=>(%d) '%v'\n", i, res)
        res = ""
    }
}

输出:

i 0 r 世
i 1 r a
i 2 r 界 ===============> would print '世a界'
i 3 r 世
i 4 r b
i 5 r c ===============> would print '世bc'
i 6 r d
i 7 r 界
i 8 r e ===============> would print 'd界e'
i 9 r f
i10 r g
i11 r 世 ===============> would print 'fg世'