連續語句中的if語句

Question

在if語句獲取問題...

func sortStudents(students: [Student], byNames: [String]) -> [Student]{ 
     var result = [Student]() 

     for name in byNames { 
      if let students = students.filter{ $0.sName == name}{ 
       if students.count > 0{ 
        result.append(students[0]) 
       } 
      } 
     } 
     return result 
    } 

Answer 1

從理論上講，這將是

if let students = students.filter({ $0.sName == name }) { ... } 

但filter沒有按」 t返回可選，無論如何，所以你不應該使用if let語法。

所以，你可以這樣做：

func sortStudents(students: [Student], byNames: [String]) -> [Student]{ 
    var result = [Student]() 

    for name in byNames { 
     let students = students.filter { $0.sName == name } 
     if students.count > 0 { 
      result.append(students[0]) 
     } 
    } 
    return result 
}