How to convert NSDate in to relative format as “Today”,“Yesterday”,“a week ago”,“a month ago”,“a year ago”?

Question

I want to convert nsdate in to relative format like \"Today\",\"Yesterday\",\"a week ago\",\"a month ago\",\"a year ago\",\"date as it is\".

I have writ

Answer 1

To avoid the 24-hour problem mentioned by Budidino to David's answer, I altered it to like this below -

- (NSString *)relativeDateStringForDate:(NSDate *)date
{

NSCalendarUnit units = NSDayCalendarUnit | NSWeekOfYearCalendarUnit |
NSMonthCalendarUnit | NSYearCalendarUnit ;
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *components1 = [cal components:(NSCalendarUnitEra|NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay) fromDate:[NSDate date]];
NSDate *today = [cal dateFromComponents:components1];

components1 = [cal components:(NSCalendarUnitEra|NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay) fromDate:date];
NSDate *thatdate = [cal dateFromComponents:components1];

// if `date` is before "now" (i.e. in the past) then the components will be positive
NSDateComponents *components = [[NSCalendar currentCalendar] components:units
                                                               fromDate:thatdate
                                                                 toDate:today
                                                                options:0];

if (components.year > 0) {
    return [NSString stringWithFormat:@"%ld years ago", (long)components.year];
} else if (components.month > 0) {
    return [NSString stringWithFormat:@"%ld months ago", (long)components.month];
} else if (components.weekOfYear > 0) {
    return [NSString stringWithFormat:@"%ld weeks ago", (long)components.weekOfYear];
} else if (components.day > 0) {
    if (components.day > 1) {
        return [NSString stringWithFormat:@"%ld days ago", (long)components.day];
    } else {
        return @"Yesterday";
    }
} else {
    return @"Today";
}
}

Basically, it creates 2 new dates without time pieces included.Then the comparison is done for "days" difference.