How can I calculate the difference between two dates?

Question

How can I calculate the days between 1 Jan 2010 and (for example) 3 Feb 2010?

Answer 1

You can find the difference by converting the date in seconds and take time interval since 1970 for this and then you can find the difference between two dates.

Answer 2

Checkout this out. It takes care of daylight saving , leap year as it used iOS calendar to calculate.You can change the string and conditions to includes minutes with hours and days.

+(NSString*)remaningTime:(NSDate*)startDate endDate:(NSDate*)endDate
{
    NSDateComponents *components;
    NSInteger days;
    NSInteger hour;
    NSInteger minutes;
    NSString *durationString;

    components = [[NSCalendar currentCalendar] components: NSCalendarUnitDay|NSCalendarUnitHour|NSCalendarUnitMinute fromDate: startDate toDate: endDate options: 0];

    days = [components day];
    hour = [components hour];
    minutes = [components minute];

    if(days>0)
    {
        if(days>1)
            durationString=[NSString stringWithFormat:@"%d days",days];
        else
            durationString=[NSString stringWithFormat:@"%d day",days];
        return durationString;
    }
    if(hour>0)
    {        
        if(hour>1)
            durationString=[NSString stringWithFormat:@"%d hours",hour];
        else
            durationString=[NSString stringWithFormat:@"%d hour",hour];
        return durationString;
    }
    if(minutes>0)
    {
        if(minutes>1)
            durationString = [NSString stringWithFormat:@"%d minutes",minutes];
        else
            durationString = [NSString stringWithFormat:@"%d minute",minutes];

        return durationString;
    }
    return @""; 
}

Answer 3

To find the difference, you need to get the current date and the date in the future. In the following case, I used 2 days for an example of the future date. Calculated by:

2 days * 24 hours * 60 minutes * 60 seconds. We expect the number of seconds in 2 days to be 172,800.

// Set the current and future date
let now = Date()
let nowPlus2Days = Date(timeInterval: 2*24*60*60, since: now)

// Get the number of seconds between these two dates
let secondsInterval = DateInterval(start: now, end: nowPlus2Days).duration

print(secondsInterval) // 172800.0