格式化UILabel上的金额

1. 将 ￥123.456 变为红色
2. 将 123 字体大小变大

/// 获取标准格式的金额
/// - Parameters:
///   - str: 金额
///   - fontSize: 字体大小
func getAttributStrFormatMoney(str: String, fontSize: CGFloat , sizeOffSet:CGFloat?=4 , fontColor:UIColor?=UIColor.red) -> NSAttributedString{
    let attributeStr = NSMutableAttributedString(string: str)
    
    //let r = Range(0..<3) //old: let _ = NSRange(location: 0, length: 3)
    let nsstr = str as NSString
    // 查找金额
    let signalRange = nsstr.range(of: "￥")
    if signalRange.length > 0 {
        let signalNumRange = NSRange(location: signalRange.location, length: attributeStr.length - signalRange.location)
        // 设置为字体颜色
        attributeStr.setAttributes([NSForegroundColorAttributeName: fontColor!], range: signalNumRange)
        
        // 查找 小数点
        let pointRange = nsstr.range(of: ".")
        // 设置 字体大小
        let numFontSize = fontSize + sizeOffSet!
        if pointRange.length > 0 {
            let numRange = NSRange(location: signalRange.location + signalRange.length, length: pointRange.location + pointRange.length - (signalRange.location + signalRange.length))
            // 设置 字体大小
            attributeStr.addAttribute(NSFontAttributeName, value: UIFont.systemFont(ofSize: numFontSize), range: numRange)
        }else{
            let numRange = NSRange(location: signalRange.location + signalRange.length, length: attributeStr.length - (signalRange.location + signalRange.length) )
            // 设置 字体大小
            attributeStr.addAttribute(NSFontAttributeName, value: UIFont.systemFont(ofSize: numFontSize), range: numRange)
        }
    }
    return attributeStr
}

使用

let str = String(format: "使用积分可抵￥%.2f", 123.456)
let attributeStr = getAttributStrFormatMoney(
    str: str,
    fontSize: 14.0
)
titleLab.attributedText = attributeStr