[Go Upper or Lower Case] Determine is a string is in lower or upper case in golang #go

upper_lower.go

func IsUpper(s string) bool {
    for _, r := range s {
        if !unicode.IsUpper(r) && unicode.IsLetter(r) {
            return false
        }
    }
    return true
}

func IsLower(s string) bool {
    for _, r := range s {
        if !unicode.IsLower(r) && unicode.IsLetter(r) {
            return false
        }
    }
    return true
}

func isFirstCharUpperCase(word string) bool {
	runes := []rune(word)
	if !unicode.IsUpper(runes[0]) || !unicode.IsLetter(runes[0]) {
		return false
	}

	return true
}