What is a rune in Go?
I’ve been googling but Golang only says in one line: rune is an alias for int32.
But how come integers are used all around like swapping cases?
The following is a function swapcase.
What is all the <= and -?
And why doesn’t switch have any arguments?
&& should mean and but what is r <= 'z'?
func SwapRune(r rune) rune {
switch {
case 'a' <= r && r <= 'z':
return r - 'a' + 'A'
case 'A' <= r && r <= 'Z':
return r - 'A' + 'a'
default:
return r
}
}
Most of them are from http://play.golang.org/p/H6wjLZj6lW
func SwapCase(str string) string {
return strings.Map(SwapRune, str)
}
I understand this is mapping rune to string so that it can return the swapped string. But I do not understand how exactly rune or byte works here.