[iOS] DateFormat > Hour > hh / h / HH / H 차이

Time Format 중 Hour를 헷갈렸어서 정리 

 

[ 요약 ]

- HH: 24 hour format / 무조건 2자리 (필요할 경우, 앞에 0 붙여줌)

- hh : 12 hour format / 무조건 2자리 (필요할 경우, 앞에 0 붙여줌)

- H : 24 hour format / 1~2 자리

- h: 12 hour format / 1~2 자리

 

[ 실험 ] 

 

우선 플레이그라운드를 열고 준비를 합니다.

 

	import Foundation
	extension DateFormatter {
	static let standard: DateFormatter = {
	let formatter = DateFormatter()
	formatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
	return formatter
	}()
	static let time_HHmm: DateFormatter = {
	let formatter = DateFormatter()
	formatter.dateFormat = "HH:mm"
	return formatter
	}()
	static let time_hhmm: DateFormatter = {
	let formatter = DateFormatter()
	formatter.dateFormat = "hh:mm"
	return formatter
	}()
	static let time_Hmm: DateFormatter = {
	let formatter = DateFormatter()
	formatter.dateFormat = "H:mm"
	return formatter
	}()
	static let time_hmm: DateFormatter = {
	let formatter = DateFormatter()
	formatter.dateFormat = "h:mm"
	return formatter
	}()
	}
	func date(year: Int, month: Int, day: Int, hour: Int, minute: Int, seconds: Int = 0) -> Date? {
	return DateFormatter.standard.date(from: "\(year)-\(month)-\(day) \(hour):\(minute):\(seconds)")
	}

view raw timeformat_hour_prepare.swift hosted with ❤ by GitHub

 

Case 1.

let sampleDate = date(year: 2021, month: 7, day: 5, hour: 22, minute: 30)!
print(DateFormatter.time_HHmm.string(from: sampleDate)) // 22:30
print(DateFormatter.time_hhmm.string(from: sampleDate)) // 10:30
print(DateFormatter.time_Hmm.string(from: sampleDate)) // 22:30
print(DateFormatter.time_hmm.string(from: sampleDate)) // 10:30

 

Case 2.

let sampleDate = date(year: 2021, month: 7, day: 5, hour: 3, minute: 3)!
print(DateFormatter.time_HHmm.string(from: sampleDate)) // 03:03
print(DateFormatter.time_hhmm.string(from: sampleDate)) // 03:03
print(DateFormatter.time_Hmm.string(from: sampleDate)) // 3:03
print(DateFormatter.time_hmm.string(from: sampleDate)) // 3:03

 

 

[ 참고 ]

참고로 AM/PM or am/pm 표현은 a 이다. 

 

12 hour format에서 07:05:45PM  은  hh:mm:ssa 로 나타낼 수 있다.

24 hour format 에서 19:05:45PM 은  HH:mm:ssa 로 나타낼 수 있다.

func timeConversion(s: String) -> String {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "hh:mm:ssa"

    let date = dateFormatter.date(from: s)
    
    dateFormatter.dateFormat = "HH:mm:ssa"
    return dateFormatter.string(from: date ?? Date())
}

// 12시간 포맷을 24시간 포맷으로 바꾸고 싶을 때
timeConversion(s: "07:05:45PM") // 19:05:45PM

 

func timeConversion(s: String) -> String {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "hh:mm:ssa"

    let date = dateFormatter.date(from: s)
    
    dateFormatter.dateFormat = "hh:mm:ss a"
    return dateFormatter.string(from: date ?? Date())
}

// PM을 한칸 띄우고 싶을 때
timeConversion(s: "07:05:45PM") // 07:05:45 PM