区间运算符可以用来表示两个操作数之间的范围集合。
1,闭区间运算符:a...b
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for iCount in 512 ... 1024 {
//从512遍历到1024(包括1024)
} |
2,半闭区间运算符:a..<b
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var fruts = [ "apple" , "orange" , "banana" ]
let iCount = fruts.count for i in 0 ..<icount{
println( "第\(i+1)个水果是\(fruts[i])" )
} |
3,字符串范围也可以使用区间运算符
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//字符串截取 let words = "Hangge.com"
//不使用区间运算符 let index = advance (words.startIndex, 4)
let index2 = advance (words.startIndex, 6)
var range1 = Range < String . Index >(start: index, end: index2)
var rangeStr1 = words.substringWithRange(range1) //ge
//使用区间运算符 var range2 = advance (words.startIndex, 4)..< advance (words.startIndex, 6)
var rangeStr2 = words.substringWithRange(range2) //ge
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4,区间运算符除了返回一个Range外,还可以接受Comparable的输入,返回ClosedInterval或HalfOpenInterval
所以我们可以用这个特性检查字符串里的字符是不是都是合法字符(比如是不是都是小写)
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let words = "Hangge.com"
let interval = "a" ... "z"
for c in words {
if !interval.contains( String (c)){
println ( "\(c)不是小写字母" )
}
} //H不是小写字母 //.不是小写字母 |