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How to create a friendly date format(for example “submitted 2 days ago”) (8)

Possible Duplicate:
How do I calculate relative time?

I want to format dates on my social web app much like Digg.com and other sites do. There, you see very friendly dates, such as:

  • just now
  • 3 minutes ago
  • one hour ago
  • 2 weeks ago
  • 6 months ago
  • etc

Before I wrap my head around creating such a thing, does anyone know of any ready-to-go script for this where I simply insert a datestamp and a friendly date text is given based on how it related to the current time?

PS: I need this in PHP, but pseudo-code or any other language is fine too.


jquery.timeago plugin

Jeff, because uses jQuery extensively, I recommend the jquery.timeago plugin.

Benefits:

  • Avoid timestamps dated "1 minute ago" even though the page was opened 10 minutes ago; timeago refreshes automatically.
  • You can take full advantage of page and/or fragment caching in your web applications, because the timestamps aren't calculated on the server.
  • You get to use microformats like the cool kids.

Just attach it to your timestamps on DOM ready:

jQuery(document).ready(function() {
    jQuery('abbr.timeago').timeago();
});

This will turn all abbr elements with a class of timeago and an ISO 8601 timestamp in the title:

<abbr class="timeago" title="2008-07-17T09:24:17Z">July 17, 2008</abbr>

into something like this:

<abbr class="timeago" title="July 17, 2008">4 months ago</abbr>

which yields: 4 months ago. As time passes, the timestamps will automatically update.

Disclaimer: I wrote this plugin, so I'm biased.


In Oracle:

select
  CC.MOD_DATETIME,
  'Last modified ' ||
  case when (sysdate - cc.mod_datetime) < 1
       then round((sysdate - CC.MOD_DATETIME)*24) || ' hours ago'
       when (sysdate - CC.MOD_DATETIME) between 1 and 7
       then round(sysdate-CC.MOD_DATETIME) || ' days ago'
       when (sysdate - CC.MOD_DATETIME) between 8 and 365
       then round((sysdate - CC.MOD_DATETIME) / 7) || ' weeks ago'
       when (sysdate - CC.MOD_DATETIME) > 365   
       then round((sysdate - CC.MOD_DATETIME) / 365) || ' years ago'
       end
from 
  customer_catalog CC

Thanks all for the answers, and sorry for the duplicate question. I did not find the duplicate when I was looking for it because I did not really know what search terms to use.

Anyways, I have my problem solved thanks to the PHP translation of the code used by . I made one tiny change in calculating the delta:

$delta = strtotime(gmdate("Y-m-d H:i:s", time())) - $time;

Since I am storing my dates in MySQL as timestamp in the GMT format, I have to use the same for calculating the CURRENT time. This makes for a timezone neutral comparison, which is exactly what is needed in my case.


There cannot be a strtotime reverse function because this is not a bijection. The source string from which you get a UNIX timestamp when you use strtotimecan be formatted in many different ways. So if you decide to reverse the function, how can you know what string format to use ? It could well be 2010-08-05 or 10 September 2000, etc. This is exactly why there is no reverse function, but as Andypandy rightly said, you have to use date()which allows you to actually define the string format you wish to end up with. I know this question is old, but I thought it deserved this answer so other users understand why there is no such function in PHP.


Well, here's how we do it on .

var ts = new TimeSpan(DateTime.UtcNow.Ticks - dt.Ticks);
double delta = Math.Abs(ts.TotalSeconds);

if (delta < 60)
{
  return ts.Seconds == 1 ? "one second ago" : ts.Seconds + " seconds ago";
}
if (delta < 120)
{
  return "a minute ago";
}
if (delta < 2700) // 45 * 60
{
  return ts.Minutes + " minutes ago";
}
if (delta < 5400) // 90 * 60
{
  return "an hour ago";
}
if (delta < 86400) // 24 * 60 * 60
{
  return ts.Hours + " hours ago";
}
if (delta < 172800) // 48 * 60 * 60
{
  return "yesterday";
}
if (delta < 2592000) // 30 * 24 * 60 * 60
{
  return ts.Days + " days ago";
}
if (delta < 31104000) // 12 * 30 * 24 * 60 * 60
{
  int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
  return months <= 1 ? "one month ago" : months + " months ago";
}
int years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
return years <= 1 ? "one year ago" : years + " years ago";

Suggestions? Comments? Ways to improve this algorithm?



Calculate relative time in C#

Jeff, your code is nice but could be clearer with constants (as suggested in Code Complete).

const int SECOND = 1;
const int MINUTE = 60 * SECOND;
const int HOUR = 60 * MINUTE;
const int DAY = 24 * HOUR;
const int MONTH = 30 * DAY;

var ts = new TimeSpan(DateTime.UtcNow.Ticks - yourDate.Ticks);
double delta = Math.Abs(ts.TotalSeconds);

if (delta < 1 * MINUTE)
  return ts.Seconds == 1 ? "one second ago" : ts.Seconds + " seconds ago";

if (delta < 2 * MINUTE)
  return "a minute ago";

if (delta < 45 * MINUTE)
  return ts.Minutes + " minutes ago";

if (delta < 90 * MINUTE)
  return "an hour ago";

if (delta < 24 * HOUR)
  return ts.Hours + " hours ago";

if (delta < 48 * HOUR)
  return "yesterday";

if (delta < 30 * DAY)
  return ts.Days + " days ago";

if (delta < 12 * MONTH)
{
  int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
  return months <= 1 ? "one month ago" : months + " months ago";
}
else
{
  int years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
  return years <= 1 ? "one year ago" : years + " years ago";
}

php strtotime reverse

This might be useful for people coming here.

/**
 * Format a timestamp to display its age (5 days ago, in 3 days, etc.).
 *
 * @param   int     $timestamp
 * @param   int     $now
 * @return  string
 */
function timetostr($timestamp, $now = null) {
    $age = ($now ?: time()) - $timestamp;
    $future = ($age < 0);
    $age = abs($age);

    $age = (int)($age / 60);        // minutes ago
    if ($age == 0) return $future ? "momentarily" : "just now";

    $scales = [
        ["minute", "minutes", 60],
        ["hour", "hours", 24],
        ["day", "days", 7],
        ["week", "weeks", 4.348214286],     // average with leap year every 4 years
        ["month", "months", 12],
        ["year", "years", 10],
        ["decade", "decades", 10],
        ["century", "centuries", 1000],
        ["millenium", "millenia", PHP_INT_MAX]
    ];

    foreach ($scales as list($singular, $plural, $factor)) {
        if ($age == 0)
            return $future
                ? "in less than 1 $singular"
                : "less than 1 $singular ago";
        if ($age == 1)
            return $future
                ? "in 1 $singular"
                : "1 $singular ago";
        if ($age < $factor)
            return $future
                ? "in $age $plural"
                : "$age $plural ago";
        $age = (int)($age / $factor);
    }
}