Swift学习之方法定义参数有默认值的时候
func testParms(first fir:String, options opt:JSONSerialization.ReadingOptions = []) -> Bool {
return true
}
此时调用的时候
方法一
let test = testParms(first: "测试")
方法二
let test2 = testParms(first: "测试", options: .mutableContainers)