【发布时间】：2010-11-11 21:32:09
【问题描述】：
我正在寻找一种简单的方法来解析在 Objective C 中包含 ISO-8601 duration 的字符串。结果应该是可用的，例如 NSTimeInterval。
ISO-8601 持续时间示例：P1DT13H24M17S，表示 1 天 13 小时 24 分 17 秒。
【问题讨论】：
标签： iphone objective-c datetime iso8601 nstimeinterval
【发布时间】：2010-11-11 21:32:09
【问题描述】：
Swift3,4,5 实现： https://github.com/Igor-Palaguta/YoutubeEngine/blob/master/Source/YoutubeEngine/Parser/NSDateComponents%2BISO8601.swift
示例：
let components = try DateComponents(ISO8601String: "P1Y2M3DT4H5M6S")
更新：修复了 DougSwith case "P3W3DT20H31M21"
【讨论】：
-
不包括数周的支持。例如，P3W3DT20H31M21 将失败。
-
@DougSmith，感谢您的反馈。添加了对周的支持，您现在可以使用 weekOfYear 属性来获取周
-
太棒了！谢谢
-
不支持毫秒。
P3W3DT20H31M21.5s例如会失败
纯 Objective C 版本...
NSString *duration = @"P1DT10H15M49S";
int i = 0, days = 0, hours = 0, minutes = 0, seconds = 0;
while(i < duration.length)
{
NSString *str = [duration substringWithRange:NSMakeRange(i, duration.length-i)];
i++;
if([str hasPrefix:@"P"] || [str hasPrefix:@"T"])
continue;
NSScanner *sc = [NSScanner scannerWithString:str];
int value = 0;
if ([sc scanInt:&value])
{
i += [sc scanLocation]-1;
str = [duration substringWithRange:NSMakeRange(i, duration.length-i)];
i++;
if([str hasPrefix:@"D"])
days = value;
else if([str hasPrefix:@"H"])
hours = value;
else if([str hasPrefix:@"M"])
minutes = value;
else if([str hasPrefix:@"S"])
seconds = value;
}
}
NSLog(@"%@", [NSString stringWithFormat:@"%d days, %d hours, %d mins, %d seconds", days, hours, minutes, seconds]);
【讨论】：
-
P1M 失败 - （为此提供 1 分钟而不是返回 1 个月）
此版本解析每个 youtube 时长而不会出错。
重要提示：此版本使用 ARC。
- (NSString*)parseISO8601Time:(NSString*)duration
{
NSInteger hours = 0;
NSInteger minutes = 0;
NSInteger seconds = 0;
//Get Time part from ISO 8601 formatted duration http://en.wikipedia.org/wiki/ISO_8601#Durations
duration = [duration substringFromIndex:[duration rangeOfString:@"T"].location];
while ([duration length] > 1) { //only one letter remains after parsing
duration = [duration substringFromIndex:1];
NSScanner *scanner = [[NSScanner alloc] initWithString:duration];
NSString *durationPart = [[NSString alloc] init];
[scanner scanCharactersFromSet:[NSCharacterSet characterSetWithCharactersInString:@"0123456789"] intoString:&durationPart];
NSRange rangeOfDurationPart = [duration rangeOfString:durationPart];
duration = [duration substringFromIndex:rangeOfDurationPart.location + rangeOfDurationPart.length];
if ([[duration substringToIndex:1] isEqualToString:@"H"]) {
hours = [durationPart intValue];
}
if ([[duration substringToIndex:1] isEqualToString:@"M"]) {
minutes = [durationPart intValue];
}
if ([[duration substringToIndex:1] isEqualToString:@"S"]) {
seconds = [durationPart intValue];
}
}
return [NSString stringWithFormat:@"%02d:%02d:%02d", hours, minutes, seconds];
}
【讨论】：
-
干得好。但不得不提的是，它应该是在ARC环境下运行的。
-
你拼错了秒而不是分钟。
如果您确切知道将获得哪些字段，则可以使用sscanf() 的一次调用：
const char *stringToParse = ...;
int days, hours, minutes, seconds;
NSTimeInterval interval;
if(sscanf(stringToParse, "P%dDT%dH%dM%sS", &days, &hours, &minutes, &seconds) == 4)
interval = ((days * 24 + hours) * 60 + minutes) * 60 + seconds;
else
; // handle error, parsing failed
如果任何字段可能被省略，您需要在解析时更聪明一点，例如：
const char *stringToParse = ...;
int days = 0, hours = 0, minutes = 0, seconds = 0;
const char *ptr = stringToParse;
while(*ptr)
{
if(*ptr == 'P' || *ptr == 'T')
{
ptr++;
continue;
}
int value, charsRead;
char type;
if(sscanf(ptr, "%d%c%n", &value, &type, &charsRead) != 2)
; // handle parse error
if(type == 'D')
days = value;
else if(type == 'H')
hours = value;
else if(type == 'M')
minutes = value;
else if(type == 'S')
seconds = value;
else
; // handle invalid type
ptr += charsRead;
}
NSTimeInterval interval = ((days * 24 + hours) * 60 + minutes) * 60 + seconds;
【讨论】：
-
写一个小解析器并不是我开始寻找简单解决方案时的想法，但似乎确实没有其他办法。我认为使用带有 NSDateFormatter 的特殊格式字符串可能会有一个技巧，但它似乎不适用于时间间隔。无论如何，我最终写了一个类似的解析器。感谢大家的帮助。
-
在上面的代码示例中要记住一件小事（是的，我意识到这可能是为了证明一个观点，而不是为了实际使用）。 ISO 8601 标准允许将持续时间值指定为可以用“.”分隔的小数值（即 1.5、0.6 等）。或“，”。
稍微修改用户功能
谢尔盖·佩卡尔
+ (NSString*)parseISO8601Time:(NSString*)duration
{
NSInteger hours = 0;
NSInteger minutes = 0;
NSInteger seconds = 0;
//Get Time part from ISO 8601 formatted duration http://en.wikipedia.org/wiki/ISO_8601#Durations
if ([duration rangeOfString:@"T"].location == NSNotFound || [duration rangeOfString:@"P"].location == NSNotFound) {
NSLog(@"Time is not a part from ISO 8601 formatted duration");
return @"0:00 Error";
}
duration = [duration substringFromIndex:[duration rangeOfString:@"T"].location];
while ([duration length] > 1) { //only one letter remains after parsing
duration = [duration substringFromIndex:1];
NSScanner *scanner = [[NSScanner alloc] initWithString:duration];
NSString *durationPart = [[NSString alloc] init];
[scanner scanCharactersFromSet:[NSCharacterSet characterSetWithCharactersInString:@"0123456789"] intoString:&durationPart];
NSRange rangeOfDurationPart = [duration rangeOfString:durationPart];
if ((rangeOfDurationPart.location + rangeOfDurationPart.length) > duration.length) {
NSLog(@"Time is not a part from ISO 8601 formatted duration");
return @"0:00 Error";
}
duration = [duration substringFromIndex:rangeOfDurationPart.location + rangeOfDurationPart.length];
if ([[duration substringToIndex:1] isEqualToString:@"H"]) {
hours = [durationPart intValue];
}
if ([[duration substringToIndex:1] isEqualToString:@"M"]) {
minutes = [durationPart intValue];
}
if ([[duration substringToIndex:1] isEqualToString:@"S"]) {
seconds = [durationPart intValue];
}
}
if (hours != 0)
return [NSString stringWithFormat:@"%ld:%02ld:%02ld", (long)hours, (long)minutes, (long)seconds];
else
return [NSString stringWithFormat:@"%ld:%02ld", (long)minutes, (long)seconds];
}
【讨论】：
以下是 swift 的示例： （仅适用于小时、分钟和秒）
func parseDuration(duration: String) -> Int {
var days = 0
var hours = 0
var minutes = 0
var seconds = 0
var decisionMaker = 0
var factor = 1
let specifiers: [Character] = ["M", "H", "T", "P"]
let length = count(duration)
for i in 1...length {
let index = advance(duration.startIndex, length - i)
let char = duration[index]
for specifier in specifiers {
if char == specifier {
decisionMaker++
factor = 1
}
}
if let value = String(char).toInt() {
switch decisionMaker {
case 0:
seconds += value * factor
factor *= 10
case 1:
minutes += value * factor
factor *= 10
case 2:
hours += value * factor
factor *= 10
case 4:
days += value * factor
factor *= 10
default:
break
}
}
}
return seconds + (minutes * 60) + (hours * 3600) + (days * 3600 * 24)
}
【讨论】：
这里是 swift 3 版本的 headkaze 示例：这种格式最适合我的情况：
private func parseISO8601Time(iso8601: String) -> String {
let nsISO8601 = NSString(string: iso8601)
var days = 0, hours = 0, minutes = 0, seconds = 0
var i = 0
while i < nsISO8601.length {
var str = nsISO8601.substring(with: NSRange(location: i, length: nsISO8601.length - i))
i += 1
if str.hasPrefix("P") || str.hasPrefix("T") { continue }
let scanner = Scanner(string: str)
var value = 0
if scanner.scanInt(&value) {
i += scanner.scanLocation - 1
str = nsISO8601.substring(with: NSRange(location: i, length: nsISO8601.length - i))
i += 1
if str.hasPrefix("D") {
days = value
} else if str.hasPrefix("H") {
hours = value
} else if str.hasPrefix("M") {
minutes = value
} else if str.hasPrefix("S") {
seconds = value
}
}
}
if days > 0 {
hours += 24 * days
}
if hours > 0 {
return String(format: "%d:%02d:%02d", hours, minutes, seconds)
}
return String(format: "%d:%02d", minutes, seconds)
}
【讨论】：
我查阅了Wikipedia article 以了解 ISO-8601 的实际工作原理。我不是 Cocoa 专家，但我敢打赌，如果您可以解析该字符串并提取小时、分钟、秒、天等组件，那么将其放入 NSTimeInterval 应该很容易。棘手的部分是解析它。我可能会这样做：
首先，将字符串拆分为两个单独的字符串：一个代表日期，一个代表时间。 NSString 有一个实例方法 componentsSeparatedByString:NSString ，它返回一个由你传入的参数分隔的原始 NSString 的子字符串的 NSArray。它看起来像这样：
NSString* iso8601 = /*However you're getting your string in*/
NSArray* iso8601Parts = [iso8601 componentsSeparatedByString:@"T"];
接下来，在 iso8601Parts 的第一个元素中搜索每个可能的持续时间指标（Y、M、W 和 D）。当你找到一个时，抓取所有前面的数字（可能还有一个小数点），将它们转换为浮点数，并将它们存储在某个地方。请记住，如果只有一个时间元素，那么 iso8601Parts[0] 将是空字符串。
然后，执行相同的操作，在 iso8601Parts 的第二个元素中查找可能的时间指示符（H、M、S）中的时间部分。请记住，如果只有一天组件（即原始字符串中没有“T”字符），则 iso8601Parts 的长度仅为 1，并且尝试访问第二个元素将导致越界异常.
一个 NSTimeInterval 只是一个很长的存储秒数，因此将您提取的单个片段转换为秒，将它们加在一起，将它们存储在您的 NSTimeInterval 中，然后就可以设置了。
抱歉，我知道您要求用一种“简单”的方式来做这件事，但根据我（诚然是轻松的）搜索和对 API 的了解，这是最简单的方法。
【讨论】：
快速而肮脏的实现
- (NSInteger)integerFromYoutubeDurationString:(NSString*)duration{
if(duration == nil){
return 0;
}
NSString *startConst = @"PT";
NSString *hoursConst = @"H";
NSString *minutesConst = @"M";
NSString *secondsConst = @"S";
NSString *hours = nil;
NSString *minutes = nil;
NSString *seconds = nil;
NSInteger totalSeconds = 0;
NSString *clean = [duration componentsSeparatedByString:startConst][1];
if([clean containsString:hoursConst]){
hours = [clean componentsSeparatedByString:hoursConst][0];
clean = [clean componentsSeparatedByString:hoursConst][1];
totalSeconds = [hours integerValue]*3600;
}
if([clean containsString:minutesConst]){
minutes = [clean componentsSeparatedByString:minutesConst][0];
clean = [clean componentsSeparatedByString:minutesConst][1];
totalSeconds = totalSeconds + [minutes integerValue]*60;
}
if([clean containsString:secondsConst]){
seconds = [clean componentsSeparatedByString:secondsConst][0];
totalSeconds = totalSeconds + [seconds integerValue];
}
return totalSeconds;
}
【讨论】：
已经有了答案，但我最终使用NSScanner 实现了另一个版本。此版本忽略年和月，因为它们无法转换为秒数。
static NSTimeInterval timeIntervalFromISO8601Duration(NSString *duration) {
NSTimeInterval timeInterval = 0;
NSScanner *scanner = [NSScanner scannerWithString:duration];
NSCharacterSet *designators = [NSCharacterSet characterSetWithCharactersInString:@"PYMWDTHMS"];
BOOL isScanningTime = NO;
while (![scanner isAtEnd]) {
double scannedNumber = 0;
BOOL didScanNumber = [scanner scanDouble:&scannedNumber];
NSString *scanned = nil;
if ([scanner scanCharactersFromSet:designators intoString:&scanned]) {
if (didScanNumber) {
switch ([scanned characterAtIndex:0]) {
case 'D':
timeInterval += scannedNumber * 60 * 60 * 24;
break;
case 'H':
timeInterval += scannedNumber * 60 * 60;
break;
case 'M':
if (isScanningTime) {
timeInterval += scannedNumber * 60;
}
break;
case 'S':
timeInterval += scannedNumber;
break;
default:
break;
}
}
if ([scanned containsString:@"T"]) {
isScanningTime = YES;
}
}
}
return timeInterval;
}
【讨论】：
现在在Swift！ （是的，它有点长，但它可以处理所有情况和单数/复数）。
处理年、月、周、日、小时、分钟和秒！
func convertFromISO8601Duration(isoValue: AnyObject) -> String? {
var displayedString: String?
var hasHitTimeSection = false
var isSingular = false
if let isoString = isoValue as? String {
displayedString = String()
for val in isoString {
if val == "P" {
// Do nothing when parsing the 'P'
continue
}else if val == "T" {
// Indicate that we are now dealing with the 'time section' of the ISO8601 duration, then carry on.
hasHitTimeSection = true
continue
}
var tempString = String()
if val >= "0" && val <= "9" {
// We need to know whether or not the value is singular ('1') or not ('11', '23').
if let safeDisplayedString = displayedString as String!
where count(displayedString!) > 0 && val == "1" {
let lastIndex = count(safeDisplayedString) - 1
let lastChar = safeDisplayedString[advance(safeDisplayedString.startIndex, lastIndex)]
//test if the current last char in the displayed string is a space (" "). If it is then we will say it's singular until proven otherwise.
if lastChar == " " {
isSingular = true
} else {
isSingular = false
}
}
else if val == "1" {
// if we are just dealing with a '1' then we will say it's singular until proven otherwise.
isSingular = true
}
else {
// ...otherwise it's a plural duration.
isSingular = false
}
tempString += "\(val)"
displayedString! += tempString
} else {
// handle the duration type text. Make sure to use Months & Minutes correctly.
switch val {
case "Y", "y":
if isSingular {
tempString += " Year "
} else {
tempString += " Years "
}
break
case "M", "m":
if hasHitTimeSection {
if isSingular {
tempString += " Minute "
} else {
tempString += " Minutes "
}
}
else {
if isSingular {
tempString += " Month "
} else {
tempString += " Months "
}
}
break
case "W", "w":
if isSingular {
tempString += " Week "
} else {
tempString += " Weeks "
}
break
case "D", "d":
if isSingular {
tempString += " Day "
} else {
tempString += " Days "
}
break
case "H", "h":
if isSingular {
tempString += " Hour "
} else {
tempString += " Hours "
}
break
case "S", "s":
if isSingular {
tempString += " Second "
} else {
tempString += " Seconds "
}
break
default:
break
}
// reset our singular flag, since we're starting a new duration.
isSingular = false
displayedString! += tempString
}
}
}
return displayedString
}
【讨论】：
Swift 4.2 版本
适用于年、月、日、小时、分钟、秒。 秒数可以是浮点数。
extension String{
public func parseISO8601Time() -> Duration {
let nsISO8601 = NSString(string: self)
var days = 0, hours = 0, minutes = 0, seconds: Float = 0, weeks = 0, months = 0, years = 0
var i = 0
var beforeT:Bool = true
while i < nsISO8601.length {
var str = nsISO8601.substring(with: NSRange(location: i, length: nsISO8601.length - i))
i += 1
if str.hasPrefix("P") || str.hasPrefix("T") {
beforeT = !str.hasPrefix("T")
continue
}
let scanner = Scanner(string: str)
var value: Float = 0
if scanner.scanFloat(&value) {
i += scanner.scanLocation - 1
str = nsISO8601.substring(with: NSRange(location: i, length: nsISO8601.length - i))
i += 1
if str.hasPrefix("Y") {
years = Int(value)
} else if str.hasPrefix("M") {
if beforeT{
months = Int(value)
}else{
minutes = Int(value)
}
} else if str.hasPrefix("W") {
weeks = Int(value)
} else if str.hasPrefix("D") {
days = Int(value)
} else if str.hasPrefix("H") {
hours = Int(value)
} else if str.hasPrefix("S") {
seconds = value
}
}
}
return Duration(years: years, months: months, weeks: weeks, days: days, hours: hours, minutes: minutes, seconds: seconds)
}
持续时间结构：
public struct Duration {
let daysInMonth: Int = 30
let daysInYear: Int = 365
var years: Int
var months: Int
var weeks: Int
var days: Int
var hours: Int
var minutes: Int
var seconds: Float
public func getMilliseconds() -> Int{
return Int(round(seconds*1000)) + minutes*60*1000 + hours*60*60*1000 + days*24*60*60*1000 + weeks*7*24*60*60*1000 + months*daysInMonth*24*60*60*1000 + years*daysInYear*24*60*60*1000
}
public func getFormattedString() -> String{
var formattedString = ""
if years != 0{
formattedString.append("\(years)")
formattedString.append(" ")
formattedString.append(years == 1 ? "year".localized() : "years".localized())
formattedString.append(" ")
}
if months != 0{
formattedString.append("\(months)")
formattedString.append(" ")
formattedString.append(months == 1 ? "month".localized() : "months".localized())
formattedString.append(" ")
}
if weeks != 0{
formattedString.append("\(weeks)")
formattedString.append(" ")
formattedString.append(weeks == 1 ? "week".localized() : "weeks".localized())
formattedString.append(" ")
}
if days != 0{
formattedString.append("\(days)")
formattedString.append(" ")
formattedString.append(days == 1 ? "day".localized() : "days".localized())
formattedString.append(" ")
}
if seconds != 0{
formattedString.append(String(format: "%02d:%02d:%.02f", hours, minutes, seconds))
}else{
formattedString.append(String(format: "%02d:%02d", hours, minutes))
}
return formattedString
}
}
【讨论】：