Fuzzy date algorithm

问题:

I'm looking for a fuzzy date algorithm. I just started writing one and realised what a tedious task it is. It quickly degenerated into a lot of horrid code to cope with special cases like the difference between "yesterday", "last week" and "late last month" all of which can (in some cases) refer to the same day but are individually correct based on today's date.

I feel sure there must be an open source fuzzy date formatter but I can't find it. Ideally I'd like something using NSDate (OSX/iPhone) and its formatters but that isn't the difficult bit. Does anyone know of a fuzzy date formatter taking any time period relative to now and returning a string like (but not limited to):

• a few moments ago
• in the last five minutes
• earlier today
• this morning
• last night
• last week
• last wednesday
• early last month
• june last year
• a couple of years ago

In an ideal world I'd like the string to be as rich as possible (i.e. returning random variants on "Just a moment ago" such as "just now").

Clarification. I'm looking for something more subtle than basic buckts and strings. I want something that knows "yesterday" and "last wednesday" can both refer to the same period but only one is correct when today is Thursday.

回答1:

This question should get you started. It has the code this very site uses to calculate its relative time. It may not have the specific ranges you want, but they are easy enough to add once you got it setup.

回答2:

There is a property in NSDateFormatter - "doesRelativeDateFormatting". It appears only in 10.6/iOS4.0 and later but it will format a date into a relative date in the correct locale.

From Apple's Documentation:

If a date formatter uses relative date formatting, where possible it replaces the date component of its output with a phrase—such as “today” or “tomorrow”—that indicates a relative date. The available phrases depend on the locale for the date formatter; whereas, for dates in the future, English may only allow “tomorrow,” French may allow “the day after the day after tomorrow,” as illustrated in the following example.

Code

The following is code that will print out a good number of the relative strings for a given locale.

NSLocale *locale = [NSLocale currentLocale];
//    NSLocale *locale = [[[NSLocale alloc] initWithLocaleIdentifier:@"fr_FR"] autorelease];

NSDateFormatter *relativeDateFormatter = [[NSDateFormatter alloc] init];
[relativeDateFormatter setTimeStyle:NSDateFormatterNoStyle];
[relativeDateFormatter setDateStyle:NSDateFormatterMediumStyle];
[relativeDateFormatter setDoesRelativeDateFormatting:YES];
[relativeDateFormatter setLocale:locale];

NSDateFormatter *normalDateFormatter = [[NSDateFormatter alloc] init];
[normalDateFormatter setTimeStyle:NSDateFormatterNoStyle];
[normalDateFormatter setDateStyle:NSDateFormatterMediumStyle];
[normalDateFormatter setDoesRelativeDateFormatting:NO];
[normalDateFormatter setLocale:locale];

NSString * lastUniqueString = nil;

for ( NSTimeInterval timeInterval = -60*60*24*400; timeInterval < 60*60*24*400; timeInterval += 60.0*60.0*24.0 )
{
    NSDate * date = [NSDate dateWithTimeIntervalSinceNow:timeInterval];

    NSString * relativeFormattedString = [relativeDateFormatter stringForObjectValue:date];
    NSString * formattedString = [normalDateFormatter stringForObjectValue:date];

    if ( [relativeFormattedString isEqualToString:lastUniqueString] || [relativeFormattedString isEqualToString:formattedString] )
        continue;

    NSLog( @"%@", relativeFormattedString );
    lastUniqueString = relativeFormattedString;
}

Notes:

• A locale is not required
• There are not that many substitutions for English. At the time of writing there are: "Yesterday, Today, Tomorrow". Apple may include more in the future.
• It's fun to change the locale and see what is available in other languages (French has a few more than English, for example)
• If on iOS, you might want to subscribe to UIApplicationSignificantTimeChangeNotification

Interface Builder

You can set the "doesRelativeDateFormatting" property in Interface Builder:

• Select your NSDateFormatter and choose the "Identity Inspector" tab of the Inspector Palette (the last one [command-6]).
• Under the sub-section named "User Defined Runtime Attributes", you can add your own value for a key on the selected object (in this case, your NSDateFormatter instance). Add "doesRelativeDateFormatting", choose a "Boolean" type, and make sure it's checked.
• Remember: It may look like it didn't work at all, but that might because there are only a few substituted values for your locale. Try at least a date for Yesterday, Today, and Tomorrow before you decide if it's not set up right.

回答3:

You might want to look at Rail's distance_of_time_in_words function in date_helper.rb, which I've pasted below.

# File vendor/rails/actionpack/lib/action_view/helpers/date_helper.rb, line 59
def distance_of_time_in_words(from_time, to_time = 0, include_seconds = false, options = {})
 from_time = from_time.to_time if from_time.respond_to?(:to_time)
 to_time = to_time.to_time if to_time.respond_to?(:to_time)
 distance_in_minutes = (((to_time - from_time).abs)/60).round
 distance_in_seconds = ((to_time - from_time).abs).round

 I18n.with_options :locale => options[:locale], :scope => 'datetime.distance_in_words''datetime.distance_in_words' do |locale|
   case distance_in_minutes
     when 0..1
       return distance_in_minutes == 0 ?
              locale.t(:less_than_x_minutes, :count => 1) :
              locale.t(:x_minutes, :count => distance_in_minutes) unless include_seconds

       case distance_in_seconds
         when 0..4   then locale.t :less_than_x_seconds, :count => 5
         when 5..9   then locale.t :less_than_x_seconds, :count => 10
         when 10..19 then locale.t :less_than_x_seconds, :count => 20
         when 20..39 then locale.t :half_a_minute
         when 40..59 then locale.t :less_than_x_minutes, :count => 1
         else             locale.t :x_minutes,           :count => 1
       end

     when 2..44           then locale.t :x_minutes,      :count => distance_in_minutes
     when 45..89          then locale.t :about_x_hours,  :count => 1
     when 90..1439        then locale.t :about_x_hours,  :count => (distance_in_minutes.to_f / 60.0).round
     when 1440..2879      then locale.t :x_days,         :count => 1
     when 2880..43199     then locale.t :x_days,         :count => (distance_in_minutes / 1440).round
     when 43200..86399    then locale.t :about_x_months, :count => 1
     when 86400..525599   then locale.t :x_months,       :count => (distance_in_minutes / 43200).round
     when 525600..1051199 then locale.t :about_x_years,  :count => 1
     else                      locale.t :over_x_years,   :count => (distance_in_minutes / 525600).round
   end
 end
end

回答4:

So, here is the category I wrote on NSDate for those who are still interested. The problem is one of those that becomes a little quixotic. It is basically a huge switch statment (although I implemented it in a series of cascading if()s to keep it more readable.

For each time period I then select from a random set of ways of telling the time.

All in all, this delighted a few of our users but I'm not sure it was worth the effort.

NSTimeInterval const kTenSeconds = (10.0f );
NSTimeInterval const kOneMinute = (60.0f);
NSTimeInterval const kFiveMinutes = (5.0f*60.0f);
NSTimeInterval const kFifteenMinutes = (15.0f*60.0f) ;
NSTimeInterval const kHalfAnHour = (30.0f*60.0f) ;
NSTimeInterval const kOneHour = 3600.0f;    // (60.0f * 60.0f);
NSTimeInterval const kHalfADay = (3600.0f * 12.0f);
NSTimeInterval const kOneDay = (3600.0f * 24.0f);
NSTimeInterval const kOneWeek = (3600.0f * 24.0f * 7.0f);

@implementation NSDate (Fuzzy)

-(NSString*)fuzzyStringRelativeToNow;
{
    static NSArray* secondsStrings;
    static NSArray* minuteStrings;
    static NSArray* fiveMinuteStrings;
    static NSArray* halfHourStrings;
    static NSArray* earlyMonthStrings;

    NSTimeInterval timeFromNow = [self timeIntervalSinceNow];
    if((timeFromNow < 0))       // In the past
    {
        timeFromNow = - timeFromNow;

        if ( (timeFromNow <  kTenSeconds))
        {
            if(!secondsStrings)
            {   
                secondsStrings = [[NSArray arrayWithObjects:@"just now",
                                                            //@"a few seconds ago",
                                                            //@"right this instant",
                                                            @"moments ago",
                                                            nil] retain];
            }

            unsigned int index = random() % ([secondsStrings count] - 1);
            return [secondsStrings objectAtIndex:index];
        }

        if ( (timeFromNow < kOneMinute))
        {
            if(!minuteStrings)
            {

                minuteStrings = [[NSArray arrayWithObjects:@"just now",
                                  @"very recently",
                                  @"in the last minute",
                                  nil] retain];
            }

            unsigned int index = random() % ([minuteStrings count] - 1);
            return [minuteStrings objectAtIndex:index];
        }

        if (timeFromNow < kFiveMinutes)
        {
            if(!fiveMinuteStrings)
            {
                fiveMinuteStrings = [[NSArray arrayWithObjects:@"just now",
                                      @"very recently",
                                      //@"in the last minute",
                                      @"a few minutes ago",
                                      //@"in the last five minutes",
                                      nil] retain];
            }
            unsigned int index = random() % ([fiveMinuteStrings count] - 1);
            return [fiveMinuteStrings objectAtIndex:index];
        }

        if (timeFromNow < kFifteenMinutes)
        {
            return @"in the last 15 minutes";
        }

        if (timeFromNow < kHalfAnHour)
        {
            if(!halfHourStrings)
            {
                halfHourStrings = [[NSArray arrayWithObjects:@"in the last half hour",
                                                            //@"in the last half an hour",
                                                            @"in the last 30 minutes",
                                                            //@"about half an hour ago",
                                                            @"fairly recently",
                                                            nil] retain];
            }
            unsigned int index = random() % ([halfHourStrings count] - 1);
            return [halfHourStrings objectAtIndex:index];
        }

        if (timeFromNow < kOneHour)
        {
            return @"in the last hour";
        }

        if ((timeFromNow < (kOneHour + kFiveMinutes)) && (timeFromNow > (kOneHour - kFiveMinutes)))
        {
            return @"about an hour ago";
        }

        if((timeFromNow < ((kOneHour*2.0f) + kFiveMinutes ))&& (timeFromNow > ((kOneHour*2.0f) - kFiveMinutes)))
        {
            return @"a couple of hours ago";
        }

        // Now we're over an hour, we need to calculate a few specific dates to compare against

        NSDate *today = [NSDate date];

        NSCalendar *gregorian = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];

        NSUInteger unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit;
        NSDateComponents* todayComponents = [gregorian components:unitFlags fromDate:today];

        todayComponents.hour = 12;

        NSDate* noonToday = [gregorian dateFromComponents:todayComponents];


        NSTimeInterval timeSinceNoonToday = [self timeIntervalSinceDate:noonToday];

        if (timeSinceNoonToday > 0)                         // sometime since noon
        {
            if (timeSinceNoonToday > kOneHour * 9)          // i.e. after 9pm today
                return @"earlier tonight";
            if (timeSinceNoonToday > kOneHour * 7)          // i.e. after 7pm today
                return @"earlier this evening";
            if (timeSinceNoonToday < kOneHour * 1)          // between noon and 1pm
                return @"early this afternoon";

            return @"this afternoon";
        }


        NSTimeInterval timeSinceMidnight = kHalfADay -timeSinceNoonToday;   // Note sign is reversed.   

        if ((timeSinceNoonToday < 0) & (timeSinceNoonToday > -kHalfADay))       // between midnight and noon today
        {
            if (timeSinceMidnight < kFiveMinutes)
                return @"around midnight";
            if (timeSinceMidnight < kOneHour * 2)           // up to 2am
                return @"very early this morning";
            if (timeSinceMidnight < kOneHour * 5)           // up to 5am
                return @"early this morning";
            else if (timeSinceMidnight < kOneHour * 11)
                return @"late this morning";
            else
                return @"this morning";
        }


        // NSTimeInterval timeSinceNoonYesterday = timeSinceNoonToday - kOneDay;

        // timeSinceMidnight = -timeSinceMidnight;

        if (timeSinceMidnight < kOneHour * 24)      // not the day before...
        {

            if (timeSinceMidnight < kFiveMinutes)
                return @"around midnight";
            if (timeSinceMidnight < kFifteenMinutes)
                return @"just before midnight";
            if (timeSinceMidnight < kOneHour * 2)           // after 10pm
                return @"late last night";
            if (timeSinceMidnight < kOneHour * 5)           // After 7
                return @"yesterday evening";
            else if (timeSinceMidnight < kOneHour * 7)
                return @"yesterday evening";                // after 5pm
            else if (timeSinceMidnight < kOneHour * 7)
                return @"yesterday evening";                // after 5pm
            else if (timeSinceMidnight < kOneHour * 10)
                return @"yesterday afternoon";              // after 5pm
            else if (timeSinceMidnight < kOneHour * 12)
                return @"early yesterday afternoon";        // before 1pm
            else if (timeSinceMidnight < kOneHour * 13)
                return @"late yesterday morning";           // after 11m
            else if (timeSinceMidnight < kOneHour * 17)
                return @"yesterday morning";                
            else 
                return @"early yesterday morning";
        }

        NSDateFormatter* formatter = [[[NSDateFormatter alloc] init] autorelease];

        int integerSeconds = timeSinceMidnight;
        int integerDay = kOneDay;
        int secondsIntoDay = integerSeconds % integerDay;
        NSString* formatString = @"last %@";

        if (timeFromNow < kOneWeek)
        {
            if (secondsIntoDay < kFifteenMinutes)
                formatString = @"around midnight on %@";
            //else if (secondsIntoDay < kFifteenMinutes)
            //  formatString = @"just before midnight on %@";
            else if (secondsIntoDay < kOneHour * 2)         // after 10pm
                formatString = @"late on %@ night";
            else if (secondsIntoDay < kOneHour * 5)         // After 7
                formatString = @"on %@ evening";
            else if (secondsIntoDay < kOneHour * 10)
                formatString = @"on %@ afternoon";              // after 5pm
            else if (secondsIntoDay < kOneHour * 12)
                formatString = @"early on %@ afternoon";        // before 1pm
            else if (secondsIntoDay < kOneHour * 13)
                formatString = @"late on %@ morning";           // after 11am
            else if (secondsIntoDay < kOneHour * 17)
                formatString = @"on %@ morning";                
            else if (secondsIntoDay < kOneHour * 24)        // not the day before...
                formatString = @"early on %@ morning";

            [formatter setDateFormat:@"EEEE"];  /// EEEE is long format of day of the week see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
            return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]]; 
        }

        //formatString = @"on %@ the week before last";
        /*if (secondsIntoDay < kOneHour * 2)            // after 10pm
            formatString = @"early on %@ the week before last";
        else if (timeSinceMidnight > kOneHour * 13)
            formatString = @"late on %@ the week before last";          // after 11m*/

        //if (timeFromNow < kOneWeek * 2)
        //{
        //  [formatter setDateFormat:@"EEE"];           /// EEE is short format of day of the week see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
        //  return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]]; 
        //}

        if (timeFromNow < kOneWeek * 2)
            {
            return @"the week before last";
            }

        NSDateComponents* myComponents = [gregorian components:unitFlags fromDate:self];

        int monthsAgo = myComponents.month - todayComponents.month;

        int yearsAgo = myComponents.year - todayComponents.year;
        if (yearsAgo == 0)
        {
            if (monthsAgo == 0)
            {
                if(myComponents.day > 22)
                    return @"late this month";
                if(myComponents.day < 7)
                {

                    if(!earlyMonthStrings)
                    {   
                        earlyMonthStrings = [[NSArray arrayWithObjects:@"earlier this month",
                                                                       //@"at the beginning of the month",
                                                                       @"early this month",
                                                                       nil] retain];
                    }

                    unsigned int index = random() % ([earlyMonthStrings count] - 1);
                    return [earlyMonthStrings objectAtIndex:index];
                }
                return @"earlier this month";
            }

            if (monthsAgo == 1)
            {
                if(myComponents.day > 22)
                    return @"late last month";
                if(myComponents.day < 7)
                    return @"early last month";
                return @"last month";
            }

            formatString  = @"in %@ this year";
            /*if(myComponents.day > 22)
                formatString  = @"late in %@ this year";
            if(myComponents.day < 7)
                formatString  = @"early in %@ this year";*/


            [formatter setDateFormat:@"MMMM"];          /// MMM is longformat of month see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
            return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]];  
        }

        if (yearsAgo == 1)
        {
            formatString  = @"in %@ last year";
            /*if(myComponents.day > 22)
                formatString  = @"late in %@ last year";
            if(myComponents.day < 7)
                formatString  = @"late in %@ last year";*/


            [formatter setDateFormat:@"MMM"];           /// MMM is longformat of month see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
            return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]];  
        }

        // int daysAgo = integerSeconds / integerDay;

    // Nothing yet...
        [formatter setDateStyle:kCFDateFormatterMediumStyle];
        //[formatter setTimeStyle:kCFDateFormatterShortStyle];

        return [NSString stringWithFormat:@"on %@",[formatter stringFromDate: self]];

    }
    else
    if(timeFromNow > 0) // The future
    {
        AICLog(kErrorLogEntry, @"FuzzyDates: Time marked as in the future: referenced date is %@, local time is %@", self, [NSDate date]);
        return @"moments ago";

    }
    else
        return @"right now";    // this seems unlikely.

    return [self description];  // should never get here.
}

sorry it took so long to post this...

回答5:

This is based on code in the Pretty and Humane date & time threads. I added handling for "last Monday, 5pm", because I like that more than x days ago. This handles past and future up to centuries. I am keen on the internationalization aspect so this needs a lot more work eventually. Calculations are in the local time zone.

public static class DateTimePretty
{
    private const int SECOND = 1;
    private const int MINUTE = 60 * SECOND;
    private const int HOUR = 60 * MINUTE;
    private const int DAY = 24 * HOUR;
    private const int WEEK = 7 * DAY;
    private const int MONTH = 30 * DAY;

    private const int YEAR = 365;

    const string now = "just now";
    const string secondsFuture = "in {0} seconds", secondsPast = "{0} seconds ago";
    const string minuteFuture = "in about a minute", minutePast = "about a minute ago";
    const string minutesFuture = "in about {0} minutes", minutesPast = "about {0} minutes ago";
    const string hourFuture = "in about an hour", hourPast = "about an hour ago";
    const string hoursFuture = "in about {0} hours", hoursPast = "about {0} hours ago";
    const string tomorrow = "tomorrow, {0}", yesterday = "yesterday, {0}";
    const string nextDay = "{0}", nextWeekDay = "next {0}", lastDay = "last {0}";
    //const string daysFuture = "in about {0} days", daysPast = "about {0} days ago";
    const string weekFuture = "in about a week", weekPast = "about a week ago";
    const string weeksFuture = "in about {0} weeks", weeksPast = "about {0} weeks ago";
    const string monthFuture = "in about a month", monthPast = "about a month ago";
    const string monthsFuture = "in about {0} months", monthsPast = "about {0} months ago";
    const string yearFuture = "in about a year", yearPast = "about a year ago";
    const string yearsFuture = "in about {0} years", yearsPast = "about {0} years ago";
    const string centuryFuture = "in about a century", centuryPast = "about a century ago";
    const string centuriesFuture = "in about {0} centuries", centuriesPast = "about {0} centuries ago";

    /// <summary>
    /// Returns a pretty version of the provided DateTime: "42 years ago", or "in 9 months".
    /// </summary>
    /// <param name="dateTime">DateTime in local time format, not Utc</param>
    /// <returns>A pretty string</returns>
    public static string GetPrettyDate(DateTime dateTime)
    {
        DateTime dateTimeNow = DateTime.Now;
        bool isFuture = (dateTimeNow.Ticks < dateTime.Ticks);
        var ts = isFuture ? new TimeSpan(dateTime.Ticks - dateTimeNow.Ticks) : new TimeSpan(dateTimeNow.Ticks - dateTime.Ticks);

        double delta = ts.TotalSeconds;

        if (delta < 10)
            return now;
        if (delta < 1 * MINUTE)
            return isFuture ? string.Format(secondsFuture, ts.Seconds) : string.Format(secondsPast, ts.Seconds);
        if (delta < 2 * MINUTE)
            return isFuture ? minuteFuture : minutePast;
        if (delta < 45 * MINUTE)
            return isFuture ? string.Format(minutesFuture, ts.Minutes) : string.Format(minutesPast, ts.Minutes);
        if (delta < 2 * HOUR)
            return isFuture ? hourFuture : hourPast;
        if (delta < 7 * DAY)
        {
            string shortTime = DateTimeFormatInfo.CurrentInfo.ShortTimePattern;
            string shortWeekdayTime = "dddd, " + shortTime;
            int dtDay = (int) dateTime.DayOfWeek;
            int nowDay = (int) dateTimeNow.DayOfWeek;
            if (isFuture)
            {
                if (dtDay == nowDay)
                {
                    if (delta < DAY)
                        return string.Format(hoursFuture, ts.Hours);
                    else
                        return string.Format(nextWeekDay, dateTime.ToString(shortWeekdayTime));
                }
                else if (dtDay - nowDay == 1 || dtDay - nowDay == -6)
                    return string.Format(tomorrow, dateTime.ToString(shortTime));
                else
                    return string.Format(nextDay, dateTime.ToString(shortWeekdayTime));
            }
            else
            {
                if (dtDay == nowDay)
                {
                    if (delta < DAY)
                        return string.Format(hoursPast, ts.Hours);
                    else
                        return string.Format(lastDay, dateTime.ToString(shortWeekdayTime));
                }
                else if (nowDay - dtDay == 1 || nowDay - dtDay == -6)
                    return string.Format(yesterday, dateTime.ToString(shortTime));
                else
                    return string.Format(lastDay, dateTime.ToString(shortWeekdayTime));
            }
        }
        //if (delta < 7 * DAY)
        //    return isFuture ? string.Format(daysFuture, ts.Days) : string.Format(daysPast, ts.Days);
        if (delta < 4 * WEEK)
        {
            int weeks = Convert.ToInt32(Math.Floor((double) ts.Days / 30));
            if (weeks <= 1)
                return isFuture ? weekFuture : weekPast;
            else
                return isFuture ? string.Format(weeksFuture, weeks) : string.Format(weeksPast, weeks);
        }
        if (delta < 12 * MONTH)
        {
            int months = Convert.ToInt32(Math.Floor((double) ts.Days / 30));
            if (months <= 1)
                return isFuture ? monthFuture : monthPast;
            else
                return isFuture ? string.Format(monthsFuture, months) : string.Format(monthsPast, months);
        }

        // Switch to days to avoid overflow
        delta = ts.TotalDays;
        if (delta < 100 * YEAR)
        {
            int years = Convert.ToInt32(Math.Floor((double) ts.TotalDays / 365.25));
            if (years <= 1)
                return isFuture ? yearFuture : yearPast;
            else
                return isFuture ? string.Format(yearsFuture, years) : string.Format(yearsPast, years);
        }
        else
        {
            int centuries = Convert.ToInt32(Math.Floor((double) ts.TotalDays / 365.2425));
            if (centuries <= 1)
                return isFuture ? centuryFuture : centuryPast;
            else
                return isFuture ? string.Format(centuriesFuture, centuries) : string.Format(centuriesPast, centuries);
        }
    }
}

回答6:

I am not sure why you say it would be a horrid coding practice. Each of the return strings are actually a subset of the parent set, so you can quite elegantly do this in a if/elseif chain.

if timestamp < 5sec
    "A moment ago"
elseif timestamp < 5min 
    "Few minutes ago"
elseif timestamp < 12hr && timestamp < noon
    "Today Morning"
...
elseif timestamp < 1week 
    "Few days ago"
elseif timestamp < 1month
    "Few weeks ago"
elseif timestamp < 6month
    "Few Months ago" 
...
else
    "Really really long time ago"

回答7:

In my experience these types of date generators are not "fuzzy" at all. In fact, they are just a bunch of if statements based bands of time. For example, any time less than 30 seconds is "moments ago", 360 to 390 days is "just a year ago", etc. Some of these will use the target date to calculate the special names (June, Wednesday, etc). Sorry to dash an illusions you had.

回答8:

needless to say (but i'll say it anyway) don't use a where loop that decrements 365 days per year even on 366 day leap years (or you'll find yourself in the ranks of the Zune developers)

here is a c# version:

http://tiredblogger.wordpress.com/2008/08/21/creating-twitter-esque-relative-dates-in-c/

回答9:

I know expressing times like this has become quite popular lately, but please considering making it an option to switch been relative 'fuzzy' dates and normal absolute dates.

For example, it's useful to know that a comment was made 5 minutes ago, but it's less useful to tell me comment A was 4 hours ago and comment B was 9 hours ago when it's 11 AM and I'd rather know that comment A was written when someone woke up this morning and comment B was written by someone staying up late (assuming I know they are in my timezone).

-- EDIT: looking closer at your question you seem to have avoided this to some degree by referring to time of day instead of "X ago", but on the other hand, you may be giving a false impression if users are in different time zone, since your "this morning" may be in the middle of the night for the relevant user.

It might be cool to augment the times with relative time of day depending on the other user's timezone, but that assumes that users are willing to supply it and that it's correct.

回答10:

I was not happy with the solution in the other question. So made my own using the Date time class. IMO, its cleaner. In my tests it worked like as I wanted. Hope this helps someone.

DateTime now = DateTime.Now;

long nowticks = now.Ticks;
long thenticks = dt.Ticks;

long diff = nowticks - thenticks;

DateTime n = new DateTime(diff);

if (n.Year > 1)
{
    return n.Year.ToString() + " years ago";
}
else if (n.Month > 1)
{
    return n.Month.ToString() + " months ago";
}
else if (n.Day > 1)
{
    return n.Day.ToString() + " days ago";
}
else if (n.Hour > 1)
{
    return n.Hour.ToString() + " hours ago";
}
else if (n.Minute > 1)
{
    return n.Minute.ToString() + " minutes ago";
}
else
{
    return n.Second.ToString() + " seconds ago";
}

回答11:

This is almost always done using a giant switch statement and is trivial to implement.

Keep the following in mind:

• Always test for the smallest time span first
• Don't forget to keep your strings localizable.

回答12:

You may find the source from timeago useful. The description of the plugin is "a jQuery plugin that makes it easy to support automatically updating fuzzy timestamps (e.g. "4 minutes ago" or "about 1 day ago")."

It's essentially a JavaScript port of Rail's distance_of_time_in_words function crammed into a jQuery plugin.

回答13:

My company has this .NET library that does some of what you want in that it does very flexible date time parsing (including some relative formats) but it only does non-relative outputs.

回答14:

Check out Chrono for a Javascript heuristic date parser.

Chrono supports most date and time formats, such as:

Today, Tomorrow, Yesterday, Last Friday, etc
17 August 2013 - 19 August 2013
This Friday from 13:00 - 16.00
5 days ago
Sat Aug 17 2013 18:40:39 GMT+0900 (JST)
2014-11-30T08:15:30-05:30

https://github.com/wanasit/chrono