Swift 取子字符串

let str = "0123456��画画……％……"

let s1 = (str as Nsstring).substringFromIndex(3)

print(s1)

let index = str.startIndex.advancedBy(2)

debugPrint(index.dynamicType)

let s2 = str.substringFromIndex(index)

print(s2)

let tart = str.startIndex

let end = str.endindex.advancedBy(-1)

let s3 = str.substringWithRange(tart..<end)

print(s3)