Is this year a leap year? no, maybe this one..?

[pablodelapena]

Is there a function in PHP with which you stick in a year and it will tell you yeay or nae as to whether the said year is a leap year?

e.g: function leapyear('2004');

will output true or false for leapyear or not?

If not is there any simple way of doing the calculation? im a little stuck.

[m_tt]

if (date("L") == "1") {
    // Leap year
} else {
    // Not a leap year
}

or you can add a timestamp to check for a different year than the current one.. ie: date("L", $timestamp);

http://us4.php.net/date

[pablodelapena]

thought it'd be something along those lines but couldnt work it out...

sooo if i did this:

<?php
$timestamp = 1986;

if ($date("L",$timestamp)) {
echo "Wahoo, a leap year be here.";
} else {
echo "Nae.";
}

?>

it would tell me whether or not 1986 was a leap year?

[laserlight]

1986 corresponds to the time 1986 seconds from 1 January 1970 00:00:00 GMT

You should get the current timestamp from say, [man]time/man instead.

[m_tt]

It would be like

if (date("L", mktime(0,0,0,1,1,1986)) == 1)	{
	//	Yes
} else {
	//	No
}

Which is Jan 1st, 1986..

there are several functions you could use instead of mktime... such as strtotime("1 January 1986");

[pablodelapena]

Ok, well lets cut to the chase. I am trying to make a function which alters the timestamp according to what a user specifies through their control panel (+-GMT).

I have managed to work something to accurately change the time if they live in a time zone which is + GMT or GMT.

Eg: i have a message which is dated 21:55. The function can add whatever it likes to the hour and alter the day/month if need be.

However if the user is -GMT then im stuck as it gives me all sorts of funny times.

The messages are stored with their timestamps asfollows

day | month | year | hour | min |

and the user account has 'timezone' which is the adjustment value.

Here is my code so far. Any crit to improve would be nice and also how i could do the negative adjustment would also be good. Take your time everyone i realsie its a longer piece of code. But tis heavily commented so it should be fairly easy to work out what each part does.

			$query = "SELECT time_format, timezone FROM userinfo WHERE username='".$_SESSION['SPuserID']."'";
			//Use while objects in case we query from within a loop.
			$SQL->query_db_while($query);
			$tformat = $SQL->fetch_row_while();


			//Calculate the time difference on server time.
			$nhour = $hour+$tformat['timezone'];

			//If alteration is positive
			if ($nhour >= 24) {
			//Hour has increased to a level above that of 24:00.
			//Work out by how much and alter time accordingly.
			$dif = $nhour-24;

				if ($dif < 10) {
				$hour = "0$dif";
				}
			//That was fun, now alter the date to suit.
			$day++;

			//BUT WAIT! if date is last in month we have to alter the date back to 1 AND the month plus 1.
			if ($day == 31){
				if (($month == 2)||($month == 4)||($month == 6)||($month == 9)||($month == 11)) {
				//These months only have 30 days.
				$day	= "01";
				$month++;
					if ($month == 13) {
					$month = "01";
					$year++;
					}
				}
			} elseif(($day == 29)&&($month == 02)&&(!date("L",mktime(0,0,0,1,1,$year)))){
				//It is the 29th of Feb and the year is not a Leap year.
				//It is now march the 1st
				$month++;
				$day = "01";
			}




			//If alteration is negative
			} else if ($nhour<0){

			//This is where I want to work out the time when the adjustment is negative.

			} else {
			$hour = $nhour;
			}

[m_tt]

Have you looked into the gmdate() function? 🙂

http://us3.php.net/manual/en/function.gmdate.php

[pablodelapena]

I have and i use it alot on my own sites! (Im a GMT kid)

But basically what I want is the user to be able to have an adjustment on the server time to suit their own timezone.

[m_tt]

I've actually never done it before, never had a need to, but couldn't you just do something like:

$offset = "7" or $offset = "-7"

date("Y-m-d H:i:s", mktime(date("H")+$offset,date("i"),date("s"),date("m"),date("d"),date("Y")));

I wouldn't trust this code because i'm just making a guess, need someone elses input here 🙂

[m_tt]

or an even easier method..

$offset	= "-8";
$timezone  = (3600 * $offset);
$output	= gmdate("Y-m-d H:i:s", time() + $timezone);

[pablodelapena]

seriously? that whole function i wrote can be done in about 4 lines? Life is so unfair sometimes.

[Weedpacket]

$output=strtotime('now GMT -8 hours');

echo date("Y-m-d H:i:s", $output);

Doesn't work for timezones that are offset from GMT by a nonintegral number of hours - but such zones are offset by an integral number of minutes (at least I don't know any that are offset by seconds).

[pablodelapena]

Id only be dealing in hours. So is yours the one i want weedpacket?

[Weedpacket]

Originally posted by pablodelapena
Id only be dealing in hours. So is yours the one i want weedpacket?

Well, m@tt's code is equivalent and probably a wee bit faster; mine's easier to read, though 🙂.

[pablodelapena]

Hate to bring this back from the dead but I have come across a problem...agian.

Thanks for all your help M@tt and weed, really appreciate it but i discovered that it still does not help with what im trying to do. Iw ant to create a function which adjusts a timestamp according to various inputs from the user: the adjustment from GMT (in hours) and the format (dd/mm/yyyy or mm/dd/yyyy). You guys code is for the CURRENT time.

I store dates in the database as seperate colomns. lets take a message say might be stored as such:

day |month |year |hour |minutes |seconds

I realsie this may not be the most effective way of storing but humor me just now.

Here is what ive written so far, Ive highlighted where Im stuck and just stuck in weeds code. 🙂

function PrepareTimestamp($day,$month,$year,$hour,$minutes) {
global $SQL;

if ($_SESSION['SPuserID'] == "guest") {
//default output
	$this->timestamp = "".$month."/".$day."/".$year." ".$hour.":".$minutes;
} else {
//user specific

	$query = "SELECT time_format, timezone FROM userinfo WHERE username='".$_SESSION['SPuserID']."'";
	$SQL->query_db($query);
	$tformat = $SQL->fetch_row();


	//------------------------------------------
	//PROBLEM HERE! i dont know what to put! vvv
	//Ive just stuck Weeds code in. How can i
	//work with my individual variables to achieve
	//what it is im trying to do?
	//------------------------------------------

	$offset    = $tformat['timezone']; 
	$timezone  = (3600 * $offset); 
	$this->timestamp    = gmdate("Y-m-d H:i:s", time() + $timezone);

	//------------------------------------------
	//PROBLEM HERE! i dont know what to put! ^^^
	//------------------------------------------


	//Which order of output? day/month/year or month/day/year
	//defined in users' entry in userinfo.
	if ($tformat['time_format'] == "ddmmyyyy") {
	$this->timestamp = "".$day."/".$month."/".$year." ".$hour.":".$minutes;
	} else {
	$this->timestamp = "".$month."/".$day."/".$year." ".$hour.":".$minutes;
	}

} //end else (user specific)

//remove colon if no minutes or hours are given.
if ((empty($hour)) || (empty($minutes))) {
$this->timestamp = str_replace(":","", $this->timestamp);
}

return $this->timestamp;

} // End PrepareTimestamp();

[Weedpacket]

In this line:

$this->timestamp    = gmdate("Y-m-d H:i:s", time() + $timezone); 

replace time() with a call to mktime() and supply the bits.

[pablodelapena]

YUUUSSSSSSS!!! thank you Weedpacket!

Had to fiddle around with ti and make a few minor adjustments to it but got it workign!

Justf or your record, this is what i ahd to change (PS altered some of the layout just to make thigns easier for me to udnerstand (step by step kinda thing)).

<?php
$offset    = $tformat['timezone'];
$offset	   = ($tformat['timezone']*3600);
$timestamp = (mktime($hour, $minutes, "0", $month, $day, $year) + $offset + 3600);
$this->timestamp    = gmdate("h/d/Y H:i", $timestamp);
?>

For some odd reason i ahd to add ANOTHER 3600 secodns on, I dont know why, but if $tformat['timeszone'] was set to 0 and the times given was 17:38 then the out put was 16:38. how odd? however adding the 3600 fixes this and it works for the other values.

[nemonoman]

Boy is that ever not the best way to store dates!

Create a column mydate
as type date(14)

That will store everything in one number.

To insert or update

SET mydate=NOW()

You can then use SQL to SELECT the date in the user's prefered format:

SELECT date_format(mydate,'%m %d %y, %h:%i');

or to show in user's prefered timezone

$result=mysql_query(
"SELECT date_format(mydate + interval  $myzone hour,'%m %d %y, %h:%i')"
);

[pablodelapena]

I realsie that it probably isnt the most effective way but it was simple for me.

Im not really that sure of MySQL commands and on the whole they confuse me. However if you feel that your suggestion would be faster I'll take it on board. But if you could explain it in as simple terms as possible Id be greatful! the '%' things have thrown me:S

Sorry if its something simple I just need it explained to me. thanks.

[nemonoman]

MySQL manual...check out DATE_FORMAT