swift - 以大写形式快速显示 AM/PM

Question

我编写了以下代码来以特定格式显示日期时间：

let formatter = NSDateFormatter()
formatter.dateStyle = NSDateFormatterStyle.LongStyle
formatter.timeStyle = .MediumStyle
formatter.dateFormat = "HH:mm a 'on' MMMM dd, yyyy"
let dateString = formatter.stringFromDate(newDate!)
println(dateString)

输出

12:16 pm on July 17, 2015

我想将“pm”显示为“PM”（大写），如果手机有 24 小时格式，则不应出现 AM/PM。请帮我。

Answer 1

您可以将 DateFormatter amSymbol 和 pmSymbol 设置如下：

Xcode 8.3 • 斯威夫特 3.1

let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "h:mm a 'on' MMMM dd, yyyy"
formatter.amSymbol = "AM"
formatter.pmSymbol = "PM"

let dateString = formatter.string(from: Date())
print(dateString)   // "4:44 PM on June 23, 2016\n"

Answer 2

在一个地方添加了一些格式。希望有人得到帮助。

Xcode 12 - 斯威夫特 5.3

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

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

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