Swift3 Scanner用法之判斷是否數字、提取字符串里的數字

1、判斷是否數字

 /// 判斷是否是數字
    ///
    /// - Parameter string: <#string description#>
    /// - Returns: <#return value description#>
    class func isPurnInt(string: String) -> Bool {
        
        let scan: Scanner = Scanner(string: string)
        
        var val:Int = 0
        
        return scan.scanInt(&val) && scan.isAtEnd
        
    }

 

2、提取字符串里的數字

 /// 從字符串中提取數字
    class func getIntFromString(str:String) -> String {
        let scanner = Scanner(string: str)
        scanner.scanUpToCharacters(from: CharacterSet.decimalDigits, into: nil)
        var number :Int = 0
        
        scanner.scanInt(&number)
        
        print(number)
        return String(number)
        
    }