Swift 3版本用新的Date对象代替NSDate:

let dateFormatterGet = DateFormatter()
dateFormatterGet.dateFormat = "yyyy-MM-dd HH:mm:ss"

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MMM dd,yyyy"

let date: Date? = dateFormatterGet.date(from: "2017-02-14 17:24:26")
print(dateFormatter.string(from: date!))

编辑:在mitul-nakum建议之后

class Utils {
  class func dateFormatter(_ date: Date, _ format: String) -> String {
    let dateformat = DateFormatter()
    dateformat.dateFormat = format
    return dateformat.string(from: date)
  }
}
print(Utils.dateFormatter(Date(), "EEEE, MMM d, yyyy"))

创建类名Utils导入相同的函数，您可以使用全局访问任何地方与您的日期和格式

将@BatyrCan转换为Swift 5.3的额外格式。在Xcode 12中测试。

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm:ss"
var dateFromStr = dateFormatter.date(from: "12:16:45")!

dateFormatter.dateFormat = "hh:mm:ss a 'on' MMMM dd, yyyy"
//Output: 12:16:45 PM on January 01, 2000

dateFormatter.dateFormat = "E, d MMM yyyy HH:mm:ss Z"
//Output: Sat, 1 Jan 2000 12:16:45 +0600

dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZ"
//Output: 2000-01-01T12:16:45+0600

dateFormatter.dateFormat = "EEEE, MMM d, yyyy"
//Output: Saturday, Jan 1, 2000

dateFormatter.dateFormat = "MM-dd-yyyy HH:mm"
//Output: 01-01-2000 12:16

dateFormatter.dateFormat = "MMM d, h:mm a"
//Output: Jan 1, 12:16 PM

dateFormatter.dateFormat = "HH:mm:ss.SSS"
//Output: 12:16:45.000

dateFormatter.dateFormat = "MMM d, yyyy"
//Output: Jan 1, 2000

dateFormatter.dateFormat = "MM/dd/yyyy"
//Output: 01/01/2000

dateFormatter.dateFormat = "hh:mm:ss a"
//Output: 12:16:45 PM

dateFormatter.dateFormat = "MMMM yyyy"
//Output: January 2000

dateFormatter.dateFormat = "dd.MM.yy"
//Output: 01.01.00

//Customisable AP/PM symbols
dateFormatter.amSymbol = "am"
dateFormatter.pmSymbol = "Pm"
dateFormatter.dateFormat = "a"
//Output: Pm

// Usage
var timeFromDate = dateFormatter.string(from: dateFromStr)
print(timeFromDate)

这是一个完整的日期格式的swift扩展

extension Date {
   func getFormattedDate(format: String) -> String {
        let dateformat = DateFormatter()
        dateformat.dateFormat = format
        return dateformat.string(from: self)
    }
    
    func getFormattedDate(style: DateFormatter.Style) -> String {
         let dateformat = DateFormatter()
         dateformat.dateStyle = style
         return dateformat.string(from: self)
     }
}

使用

myDate.getFormattedDate(style: .medium) //medium, short, full, long

OR

myDate.getFormattedDate(format: "yyyy/MM/dd HH:mm:ss")

要将2016-02-29 12:24:26转换为日期，使用以下日期格式化程序:

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd hh:mm:ss"

编辑:获取输出2016年2月29日使用这个日期格式化器:

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "MMM dd, yyyy"

在iOS 15中使用如下代码:

extension Date {
    var string: String {
        if #available(iOS 15.0, *) {
            return self.formatted(date: .complete, time: .complete)
        } else {
            return self.description
        }
    }
}