1、閉區(qū)間運算符：a...b
for i in 512...1024{
//從512遍歷到1024（包括1024）
}
2、半閉區(qū)間運算符：a..<b
var fruts = ["apple","orange","banana"]
let frutsCount = fruts.count
for i in 0..< frutsCount{
print("第(i+1)個水果是(fruts[i])")
}
3、倒序循環(huán)，通過 reversed() 方法，我們可以將一個正序循環(huán)變成逆序循環(huán)。(輸出結(jié)果：3、2、1、0)
for i in (0..<4).reversed() {
print(i)
}
4、字符串范圍也可以使用區(qū)間運算符
//字符串截取
let words = "Hangge.com"
//不使用區(qū)間運算符
let index = words.index(words.startIndex, offsetBy: 4)
let index2 = words.index(words.startIndex, offsetBy: 6)
let range1 = Range(uncheckedBounds: (lower: index, upper: index2))
let rangeStr1 = words.substring(with: range1) //ge
print(rangeStr1)
//使用區(qū)間運算符
let range2 = words.index(words.startIndex, offsetBy: 4)..<words.index(words.startIndex,offsetBy: 6)
let rangeStr2 = words.substring(with: range2) //ge
print(rangeStr2)
