Swift trim space/new line（字符串过滤空格和换行符）

/// UIView's useful extensions.
///
/// Author: huangyibiao
/// Github: http://github.com/CoderJackyHuang/ /// Blog:   http://www.hybblog.com/ extension String {
/// Get the length of a string
public func hyb_length() ->Int {
return self.characters.count
}

/// 去掉字符串前后的空格，根据参数确定是否过滤换行符
///
/// - parameter trimNewline 是否过滤换行符，默认为false
public func hyb_trim(trimNewline: Bool = false) ->String {
if trimNewline {
return self.stringByTrimmingCharactersInSet(.whitespaceAndNewlineCharacterSet())
}

return self.stringByTrimmingCharactersInSet(.whitespaceCharacterSet())
}

/// 去掉字符串前面的空格，根据参数确定是否过滤换行符
///
/// - parameter trimNewline 是否过滤换行符，默认为false
public func hyb_trimLeft(trimNewline: Bool = false) ->String {
if self.isEmpty {
return self
}

var index = self.startIndex
while index != self.endIndex {
let ch = self.characters[index]
if ch == Character(" ") {
index++
continue
} else if ch == Character("\n") {
if trimNewline {
index++
continue
} else {
break
}
}

break
}

return self.substringFromIndex(index)
}

/// 去掉字符串后面的空格，根据参数确定是否过滤换行符
///
/// - parameter trimNewline 是否过滤换行符，默认为false
public func hyb_trimRight(trimNewline: Bool = false) ->String {
if self.isEmpty {
return self
}

var index = self.endIndex.predecessor()
while index != self.startIndex {
let ch = self.characters[index]
if ch == Character(" ") {
index--
continue
} else if ch == Character("\n") {
if trimNewline {
index--
continue
} else {
index++
break
}
}

break
}

return self.substringToIndex(index)
}
}