iOS Swift4如何检查字符串是否不为零且不为空？ [复制]

Question

如何在 Swift4 中检查可选字符串对象是否既不是空字符串 "" 也不是 nil？ 我最终不得不编写类似这样的奇怪检查，因为

 //object has instance variable     
 var title: String?

 //invalid comparison - cannot compare optional and non optional
 if object.title?.count > 0
 {

 }

 //valid but ugly
 if object.titleString == nil {
      //has nil title
 }
 if let title = object.title
 {
    if title.count == 0
    {
        //has a "" string
    }
 }

Answer 1

我会选择类似的东西

if let title = object.title, !title.isEmpty {
  // it's not nil nor an empty string
}