错误：二进制运算符'<='不能应用于'Int？'类型的操作数和 'INT'

问题描述：

我得到了一个名为错误：错误：二进制运算符'<='不能应用于'Int？'类型的操作数和 'INT'

Binary operator '<=' cannot be applied to operands of type 'Int?' and 'Int'

在线：if differenceOfDate.second <= 0能有人请帮助！

let fromDate = Date(timeIntervalSince1970: TimeInterval(truncating: posts[indexPath.row].postDate)) 
    let toDate = Date() 
    var calendar = Calendar.current 
    let components = Set<Calendar.Component>([.second, .minute, .hour, .day, .weekOfMonth, .month]) 
    let differenceOfDate = Calendar.current.dateComponents(components, from: fromDate, to: toDate) 

    if differenceOfDate.second <= 0 { 
     cell.DateLbl.text = "now" 
    }else if differenceOfDate.second > 0 && differenceOfDate.minute == 0 { 
     cell.DateLbl.text = "\(differenceOfDate.second)s." 
    } 
    else if differenceOfDate.minute > 0 && differenceOfDate.hour == 0 { 
     cell.DateLbl.text = "\(differenceOfDate.minute)m." 
    } 
    else if differenceOfDate.hour > 0 && differenceOfDate.day == 0 { 
     cell.DateLbl.text = "\(differenceOfDate.hour)h." 
    } 
    else if differenceOfDate.day > 0 && differenceOfDate.weekOfMonth == 0 { 
     cell.DateLbl.text = "\(differenceOfDate.day)d." 
    } 
    else if differenceOfDate.weekOfMonth > 0 && differenceOfDate.month == 0 { 
     cell.DateLbl.text = "\(differenceOfDate.weekOfMonth)w." 
    } 
    else if differenceOfDate.month > 0 { 
     cell.DateLbl.text = "\(differenceOfDate.month)m." 
    }

请查找了资料https://developer.apple .com/documentation/foundation/calendar/2292887-datecomponents，你会发现它使用'Date'类型的参数，而不是'NSDate'。 –

相关：https://stackoverflow.com/questions/41198803/how-to-convert-from-nsdatetimeintervalsince1970-to-nsdate。 –

如果我使用Date来比错误“Binary operator' Danjhi

答

你需要考虑的文档是关于“DateComponents”数据类型之一，如果你不熟悉自选您需要在自选阅读起来为好。

简而言之，DateComponents数据类型可能并不总是包含所有组件的值，因此每个成员都是可选的Int ?.这意味着它们可以包含零。

因此，您无法直接将日期组件与非可选值进行比较。你必须“打开”它们。

如果你是100％肯定，总是会有一个。第二个组件，您可以强制通过添加一个感叹号解开值：

if differenceOfDate.second! <= 0

错误：二进制运算符'<='不能应用于'Int？'类型的操作数和 'INT'

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