What is iteration over a string using for range in Go? What are the variables i and v inside the loop, and what are their data types?

In Go, the for range construct is used to iterate over collections, including strings. When iterating over a string with for i, v := range str:

• i is the index of the current character in the string, of type int.
• v is the value of the current character, of type rune (Unicode code point).

This is important because in Go, strings are sequences of bytes, and range over a string returns rune characters, correctly handling multi-byte UTF-8 characters.

Example:

str := "Привет"
for i, v := range str {
    fmt.Printf("Index: %d, Character: %c, Type: %T\n", i, v, v)
}

The output will show the byte indices of the start of each character and the characters themselves as runes.