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

You will need to work out this logic yourself. You will need to determine the number of days in between those two dates.

Here is a relatively naive approach:

+ (NSString *) dateDifference:(NSDate *)date
{
    const NSTimeInterval secondsPerDay = 60 * 60 * 24;
    NSTimeInterval diff = [date timeIntervalSinceNow] * -1.0;

    // if the difference is negative, then the given date/time is in the future
    // (because we multiplied by -1.0 to make it easier to follow later)
    if (diff < 0)
        return @"In the future";

    diff /= secondsPerDay; // get the number of days

    // if the difference is less than 1, the date occurred today, etc.
    if (diff < 1)
        return @"Today";
    else if (diff < 2)
        return @"Yesterday";
    else if (diff < 8)
        return @"Last week";
    else
        return [date description]; // use a date formatter if necessary
}

It is naive for a number of reasons:

1. It doesn't take into account leap days
2. It assumes there are 86400 seconds in a day (there is such a thing as leap seconds!)

However, this should at least help you head in the right direction. Also, avoid using get in method names. Using get in a method name typically indicates that the caller must provide their own output buffer. Consider NSArray's method, getItems:range:, and NSString's method, getCharacters:range:.