Why am I getting different types in strings?

Question

I have encountered a situation that I do not understand.

    a := "hello"
    fmt.Printf("%v %T\n",a[0],a[0])

This gives 104 uint8.

    for _,v := range a {
        fmt.Printf("%v %T\n",v,v)
    }

This gives 104 int32 for the first iteration. I don't understand why their types are not same. First one is byte, second one is rune. I expect both to be byte.

`a` is a string and not a slice of byte. And that's how `for` loops over strings work. If there wasn't a special rule for strings you couldn't range over strings at all as these are neither arrays, slices nor channels. — Volker, Mar 23 '20 at 05:59

score 3 · Answer 1 · answered Mar 22 '20 at 17:06

3

This might explain it:

https://blog.golang.org/strings

In short: if a is a string, a[i] is a byte, but here, r is a rune:

for _,r:=range a {
...
}

When you range over a string, you range over the runes of that string. To range over the bytes of a string, use:

for i:=0;i<len(a);i++ {
   // Here, a[i] is byte
}

answered Mar 22 '20 at 17:06

Burak Serdar

46,455
3
40
59

1

And a single rune can take up to 4-bytes (32-bits): https://play.golang.org/p/kmWjgfP4NAT – colm.anseo Mar 22 '20 at 17:17

Why am I getting different types in strings?

1 Answers1