Swift中去掉字符串格式数字小数点后多余的0 （自写）

func quxiaoshudianhoudeling(testNumber:String) -> String{

var outNumber = testNumber
var i = 1

if testNumber.containsString("."){
while i < testNumber.characters.count{
if outNumber.hasSuffix("0"){
outNumber.removeAtIndex(outNumber.endIndex.predecessor())
i = i + 1
}else{
break
}
}
if outNumber.hasSuffix("."){
outNumber.removeAtIndex(outNumber.endIndex.predecessor())
}
return outNumber
}
else{
return testNumber
}
}