3.Days.Ago, 2.Hours.From_Now etc Without Rails

3.days.ago, 2.hours.from_now etc without Rails?

I'm not sure if there's another gem available besides ActiveSupport, but it would be really straight-forward to make a small version yourself:

class Fixnum
  SECONDS_IN_DAY = 24 * 60 * 60

  def days
    self * SECONDS_IN_DAY
  end

  def ago
    Time.now - self
  end
end

3.days.ago #=> 2011-06-18 08:45:29 0200

from_now can be implemented like ago but with + self and weeks, hours etc. like days using different constants.

How to add 10 days to current time in Rails

Use

Time.now + 10.days

or even

10.days.from_now

Both definitely work. Are you sure you're in Rails and not just Ruby?

If you definitely are in Rails, where are you trying to run this from? Note that Active Support has to be loaded.

1 week from now at 8 o'clock

There are many ways to achieve this. Here's one:

Time.parse('8am') + 1.week

Here's another:

DateTime.now.beginning_of_day + 1.week + 8.hours

Or how about:

1.week.from_now.beginning_of_day + 8.hours

Or even:

DateTime.now.advance(days: 7).change(hour: 8)

Ruby (with Rails) convert a string of time into seconds?

What you're asking Ruby to do with Time.parse is determine a time of day. That's not what you are wanting. All of the libraries I can think of are similar in this aspect: they are interested in absolute times, not lengths of time.

To convert your strings into time formats that we can work with, I recommend using Chronic (gem install chronic). To convert to seconds, we can do everything relative to the current time, then subtract that time to get the absolute number of seconds, as desired.

def seconds_in(time)
    now = Time.now
    Chronic.parse("#{time} from now", :now => now) - now
end

seconds_in '48 hours'   # => 172,800.0
seconds_in '15 minutes' # => 900.0
seconds_in 'a lifetime' # NoMethodError, not 42 ;)

A couple quick notes:

• The from now is is why Chronic is needed — it handles natural language input.
• We're specifying now to be safe from a case where Time.now changes from the time that Chronic does it's magic and the time we subtract it from the result. It might not occur ever, but better safe than sorry here I think.

How to calculate time ago in Java?

Take a look at the PrettyTime library.

It's quite simple to use:

import org.ocpsoft.prettytime.PrettyTime;

PrettyTime p = new PrettyTime();
System.out.println(p.format(new Date()));
// prints "moments ago"

You can also pass in a locale for internationalized messages:

PrettyTime p = new PrettyTime(new Locale("fr"));
System.out.println(p.format(new Date()));
// prints "à l'instant"

As noted in the comments, Android has this functionality built into the android.text.format.DateUtils class.

Ruby or Rails find records dated two months from now

You can add the following scope to your model:

scope :expiring_soon, -> {
  date = Date.today >> 1
  where(expires_at: (date.beginning_of_month..date.end_of_month))
}

And then call the scope like this:

YourModel.expiring_soon

You might want to read about Date/Time calculations and Range queries (see 2.3.2) in Rails.

Converting timestamp to time ago in PHP e.g 1 day ago, 2 days ago...

Use example :

echo time_elapsed_string('2013-05-01 00:22:35');
echo time_elapsed_string('@1367367755'); # timestamp input
echo time_elapsed_string('2013-05-01 00:22:35', true);

Input can be any supported date and time format.

Output :

4 months ago
4 months ago
4 months, 2 weeks, 3 days, 1 hour, 49 minutes, 15 seconds ago

Function :

function time_elapsed_string($datetime, $full = false) {
    $now = new DateTime;
    $ago = new DateTime($datetime);
    $diff = $now->diff($ago);

    $diff->w = floor($diff->d / 7);
    $diff->d -= $diff->w * 7;

    $string = array(
        'y' => 'year',
        'm' => 'month',
        'w' => 'week',
        'd' => 'day',
        'h' => 'hour',
        'i' => 'minute',
        's' => 'second',
    );
    foreach ($string as $k => &$v) {
        if ($diff->$k) {
            $v = $diff->$k . ' ' . $v . ($diff->$k > 1 ? 's' : '');
        } else {
            unset($string[$k]);
        }
    }

    if (!$full) $string = array_slice($string, 0, 1);
    return $string ? implode(', ', $string) . ' ago' : 'just now';
}

Check if a date is 24 hours old

Add this const oneday = 60 * 60 * 24 * 1000 (milliseconds). Since, JS converts difference between 2 Datetime objects into milliseconds. I think that should work

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