Question

我正在快速练习，目前正在编写一个简单的功能来显示当天的日程安排。如果return语句包含值，则busyDay语句应仅包含func scheduleToday (date: String, day: String, numberOfMeetings: Int?) -> String { var meetingMessage = "" var busyDay: String! if var meetings = numberOfMeetings { if meetings > 4 { busyDay = "Today is a busy day!" } meetingMessage = "\(meetings) meetings" } else { meetingMessage = "no meetings today." } return "| \(date) - \(day) | Good morning. \(busyDay) You have \(meetingMessage)." }。我希望这可以自动完成，但事实并非如此。

numberOfMeetings

如果// | 17th of June - Wedensday | Good morning. nil You have 3 meetings.为4或更小，则返回的字符串显示为：

Summary
-----------
1. In main() am going for pthread_cond_wait().
2. In signal handler() am waking main() using pthread_cond_signal().
3. But main() is not coming out from pthread_cond_wait().

Answer 1

你可以在if添加一个else语句，将budyDay设置为空字符串

if meetings > 4 {
    busyDay = "Today is a busy day!"
} else {
    busyDay = ""
}

Answer 2

如果ternary operator为4或更少且您的代码为：

，您可以使用numberOfMeetings分配空字符串

func scheduleToday (date: String, day: String, numberOfMeetings: Int?) -> String {
var meetingMessage = ""
var busyDay: String!

    if var meetings = numberOfMeetings {

        busyDay = meetings > 4 ? "\(meetings) meetings" : ""
        meetingMessage = "\(meetings) meetings"
    } else {
        meetingMessage = "no meetings today."
    }

    return "| \(date) - \(day) |   Good morning. \(busyDay) You have \(meetingMessage)."
}


let schedule = scheduleToday("1234", "8678678", 3)  // "| 1234 - 8678678 |   Good morning.  You have 3 meetings.""

在字符串中省略nil

2 个答案: