问题
When I'm trying to list characters in an NSCharacterSet like this
print(NSCharacterSet.URLQueryAllowedCharacterSet())
it doesn't print out the characters but rather something similar to
<__NSCFCharacterSet: 0x1759b900>
回答1:
Based on another answer, here is a derived cleaner version in Swift 2.0/3.0:
extension NSCharacterSet {
var characters:[String] {
var chars = [String]()
for plane:UInt8 in 0...16 {
if self.hasMemberInPlane(plane) {
let p0 = UInt32(plane) << 16
let p1 = (UInt32(plane) + 1) << 16
for c:UTF32Char in p0..<p1 {
if self.longCharacterIsMember(c) {
var c1 = c.littleEndian
let s = NSString(bytes: &c1, length: 4, encoding: NSUTF32LittleEndianStringEncoding)!
chars.append(String(s))
}
}
}
}
return chars
}
}
Usage:
let charset = NSCharacterSet.URLQueryAllowedCharacterSet()
print(charset.characters.joinWithSeparator(""))
来源：https://stackoverflow.com/questions/34772439/see-characters-in-an-nscharacterset-swift