iOS Swift4如何检查字符串是否为零和非空?
如何检查可选字符串对象在Swift4中是否既不是空字符串“”,也不是nil?我最后不得不写这样奇怪的检查,因为iOS Swift4如何检查字符串是否为零和非空?,ios,string,swift4,Ios,String,Swift4,如何检查可选字符串对象在Swift4中是否既不是空字符串“”,也不是nil?我最后不得不写这样奇怪的检查,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.tit
//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
}
}
我会选择这样的
if let title = object.title, !title.isEmpty {
// it's not nil nor an empty string
}
看这可能是它帮助你如果!(标题?.isEmpty??true){/*你有东西吗*/}