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Last updated: Sun, 02 May 2004

XVII. Funzioni di Data e Ora

Introduzione

Puoi usare queste funzione per la data e l'ora. Queste funzioni ti permettono di scaricare la data e l'orario dal server dove gira il PHP. Puoi usare queste funzioni per formattare l'output delle date e degli orari in diversi modi.

Nota: Ricordati che queste funzioni dipendono dai settaggi locali del tuo server. Considera specialmente l'ora legale e gli anni bisestili.

Requisiti

Non sono necessarie librerie esterne per utilizzare questo modulo.

Installazione

Non è necessaria nessuna installazione per usare queste funzioni, esse fanno parte del core di PHP.

Configurazione di Runtime

Questa estensione non definisce alcuna direttiva di configurazione in php.ini

Tipi di risorse

Questa estensione non definisce alcun tipo di risorsa.

Costanti predefinite

Questa estensione non definisce alcuna costante.

Sommario
checkdate -- Verifica una data/orario gragoriana/o
date -- Formatta una data o orario locale
getdate -- Riceve informazioni su data/orario
gettimeofday -- Riceve l'orario attuale
gmdate -- Formatta una data/ora GMT/UTC
gmmktime -- Riceve l'UNIX timestamp per una data GMT
gmstrftime --  Formatta una data/ora GMT/UTC secondo i parametri locali
idate --  Format a local time/date as integer
localtime -- Riceve l'orario locale
microtime --  Restituisce l'attuale UNIX timestamp con i microsecondi
mktime -- Restituisce la UNIX timestamp per una data
strftime --  Formatta una data/orario locale accordandola/o alle impostazioni locali according to locale settings
strtotime --  Analizza le descrizioni testuali di datetime in Inglese nell'UNIX timestamp
time -- Restituisce l'attuale UNIX timestamp


add a note add a note User Contributed Notes
Funzioni di Data e Ora
nickaubert at america's biggest isp dot com
12-Apr-2004 07:13
I ran into an issue using a function that loops through an array of dates where the keys to the array are the Unix timestamp for midnight for each date.  The loop starts at the first timestamp, then incremented by adding 86400 seconds (ie. 60 x 60 x 24).  However, Daylight Saving Time threw off the accuracy of this loop, since certain days have a duration other than 86400 seconds.  I worked around it by adding a couple of lines to force the timestamp to midnight at each interval.

<?php
  $ONE_DAY = 90000;  // can't use 86400 because some days have one hour more or less
  for ( $each_timestamp = $start_time ; $each_timestamp <= $end_time ; $each_timestamp +=  $ONE_DAY) {

   /*  force midnight to compensate for daylight saving time  */
   $this_timestamp_array = getdate( $each_timestamp );
   $each_timestamp = mktime ( 0 , 0 , 0 , $this_timestamp_array[mon] , $this_timestamp_array[mday] , $this_timestamp_array[year] );

     // do some stuff...
  }
?>
pk_jsp at rediffmail dot com
12-Apr-2004 06:06
Just want to add a comment to the function datediff given by Xiven that simple difference of 2 dates as in
 $seconds = $date2 - $date1; will nor work instead the following need to be used.
 $seconds = strtotime($date2) - strtotime($date1);
scott_webster_2000 at yahoo dot com
20-Feb-2004 04:02
Here is a slight improvement over wwb_99@yahoo's entry.  (It works now.)

function date_diff($earlierDate, $laterDate) {
  //returns an array of numeric values representing days, hours, minutes & seconds respectively
  $ret=array('days'=>0,'hours'=>0,'minutes'=>0,'seconds'=>0);

  $totalsec = $laterDate - $earlierDate;
  if ($totalsec >= 86400) {
   $ret['days'] = floor($totalsec/86400);
   $totalsec = $totalsec % 86400;
  }
  if ($totalsec >= 3600) {
   $ret['hours'] = floor($totalsec/3600);
   $totalsec = $totalsec % 3600;
  }
  if ($totalsec >= 60) {
   $ret['minutes'] = floor($totalsec/60);
  }
  $ret['seconds'] = $totalsec % 60;
  return $ret;
}
php at sarge dot ch
28-Jan-2004 10:58
Additional thisone here (didn't test it yet but should work :D):

<?php
/**
 * Calculates the Difference between two timestamps
 *
 * @param integer $start_timestamp
 * @param integer $end_timestamp
 * @param integer $unit (default 0)
 * @return string
 * @access public
 */
function dateDifference($start_timestamp,$end_timestamp,$unit= 0){
  $days_seconds_star= (23 * 56 * 60) + 4.091; // Star Day
  $days_seconds_sun= 24 * 60 * 60; // Sun Day
  $difference_seconds= $end_timestamp - $start_timestamp;
  switch($unit){
   case 3: // Days
     $difference_days= round(($difference_seconds / $days_seconds_sun),2);
     return 'approx. '.$difference_hours.' Days';
   case 2: // Hours
     $difference_hours= round(($difference_seconds / 3600),2);
     return 'approx. '.$difference_hours.' Hours';
   break;
   case 1: // Minutes
     $difference_minutes= round(($difference_seconds / 60),2);
     return 'approx. '.$difference_minutes.' Minutes';
   break;
   default: // Seconds
     if($difference_seconds > 1){
       return $difference_seconds.' Seconds';
     }
     else{
       return $difference_seconds.' Second';
     }
  }
}
?>
wwb_99 at yahoo dot com
25-Jan-2004 07:12
Handy little function getting the total difference in dates.

function DateDiff($tfirst, $tsecond)
{
   //returns an array with numeric values for in an array measuring days, hours, minutes & seconds
   $ret=array();
   $totalsec=$tsecond-$tfirst;
   $ret['days']=round(($totalsec/86400));
   $totalsec=$totalsec % 86400;
   $ret['hours']=round(($totalsec/3600));
   $totalsec=$totalsec % 3600;
   $ret['minutes']=round(($totalsec/60));
   $ret['seconds']=$totalsec % 60;
   return $ret;
}
php at elmegil dot net
20-Dec-2003 04:40
A much easier way to do days diff is to use Julian Days from the Calendar functions:

$start = gregoriantojd($smon, $sday, $syear);
$end = gregoriantojd($emon, $eday, $eyear);
$daysdiff = $end - $start;

You can see the obvious ways to wrap a function around that.
vincentv at thevoid dot demon dot nl
19-Nov-2003 07:56
A rectification to the some of the functions i posted a while ago.

They do not work correctly under all circumstances (in my small test cases they worked) which is due to the fact that when you create a date using mktime, which returns a certain amount of seconds, this is not valid for every month since each month has a different amount of seconds.

The solution is to break up the original timestamp, add to it's seperate parts and create a new timestamp.

Old:
=====
function sub($timestamp, $seconds,$minutes,$hours,$days,$months,$years) {
   $mytime = mktime(1+$hours,0+$minutes,0+$seconds,1+$months,1+$days,1970+$years);
   return $timestamp - $mytime;
}
function add($timestamp, $seconds,$minutes,$hours,$days,$months,$years) {
   $mytime = mktime(1+$hours,0+$minutes,0+$seconds,1+$months,1+$days,1970+$years);
   return $timestamp + $mytime;
}
=====

New:
=====
function add($timestamp, $seconds, $minutes, $hours, $days, $months, $years) {
   $timePieces = getdate($timestamp);
   return mktime(    $timePieces["hours"] + $hours,
                   $timePieces["minutes"] + $minutes,
                   $timePieces["seconds"] + $seconds,
                   $timePieces["mon"] + $months,
                   $timePieces["mday"] + $days,
                   $timePieces["year"] + $years );
}
function sub($timestamp, $seconds, $minutes, $hours, $days, $months, $years) {
   $timePieces = getdate($timestamp);
   return mktime(    $timePieces["hours"] - $hours,
                   $timePieces["minutes"] - $minutes,
                   $timePieces["seconds"] - $seconds,
                   $timePieces["mon"] - $months,
                   $timePieces["mday"] - $days,
                   $timePieces["year"] - $years );
}
=====

Regards,
- Vincent
CodeDuck at gmx dot net
07-Nov-2003 12:30
in reply to dkan at netscreen dot com 29-Aug-2003 07:40
> Zero-padding is easier to read and less complicated if you
> use the substr() function instead of an if-then statement.

my two versions of printtime with padding:

<?
function printtime() {
   $timenow = getdate();
   printf(
     '%02d %02d %02d',
     $timenow["hours"],
     $timenow["minutes"],
     $timenow["seconds"]
   );
}
?>

or the better one:
<?
function printtime() {
   echo date('H i s');
}
?>
Xiven
02-Oct-2003 12:09
One thing PHP really lacks IMHO is an equivalent of ASP's "DateDiff" function.  Here's a function that comes close to duplicating the functionality:

<?php
function datediff($interval, $date1, $date2) {
   // Function roughly equivalent to the ASP "DateDiff" function
   $seconds = $date2 - $date1;
  
   switch($interval) {
       case "y":
           list($year1, $month1, $day1) = split('-', date('Y-m-d', $date1));
           list($year2, $month2, $day2) = split('-', date('Y-m-d', $date2));
           $time1 = (date('H',$date1)*3600) + (date('i',$date1)*60) + (date('s',$date1));
           $time2 = (date('H',$date2)*3600) + (date('i',$date2)*60) + (date('s',$date2));
           $diff = $year2 - $year1;
           if($month1 > $month2) {
               $diff -= 1;
           } elseif($month1 == $month2) {
               if($day1 > $day2) {
                   $diff -= 1;
               } elseif($day1 == $day2) {
                   if($time1 > $time2) {
                       $diff -= 1;
                   }
               }
           }
           break;
       case "m":
           list($year1, $month1, $day1) = split('-', date('Y-m-d', $date1));
           list($year2, $month2, $day2) = split('-', date('Y-m-d', $date2));
           $time1 = (date('H',$date1)*3600) + (date('i',$date1)*60) + (date('s',$date1));
           $time2 = (date('H',$date2)*3600) + (date('i',$date2)*60) + (date('s',$date2));
           $diff = ($year2 * 12 + $month2) - ($year1 * 12 + $month1);
           if($day1 > $day2) {
               $diff -= 1;
           } elseif($day1 == $day2) {
               if($time1 > $time2) {
                   $diff -= 1;
               }
           }
           break;
       case "w":
           // Only simple seconds calculation needed from here on
           $diff = floor($seconds / 604800);
           break;
       case "d":
           $diff = floor($seconds / 86400);
           break;
       case "h":
           $diff = floor($seconds / 3600);
           break;       
       case "i":
           $diff = floor($seconds / 60);
           break;       
       case "s":
           $diff = $seconds;
           break;       
   }   
   return $diff;
}
?>
dkan at netscreen dot com
29-Aug-2003 07:40
Zero-padding is easier to read and less complicated if you use the substr() function instead of an if-then statement.

function printtime() {
   $timenow = getdate();
   $hours = substr("0" . $timenow["hours"], -2);
   $minutes = substr("0" . $timenow["minutes"], -2);
   $seconds = substr("0" . $timenow["seconds"], -2);

   print($hours . " " . $minutes . " " . $seconds);
}
bitbuster at example dot com
24-Jul-2003 02:01
If you have to compare timestamps, I suggest you do it inside the database.. postgres, for example, allows statements like this:

select (current_timestamp < (select zeitdatum from time_test where zahl=5) );
menaurus at gmx dot de
16-Jul-2003 10:37
The argument has to be in the standard mysql format (y-m-d)...

function age($date) {

if (!$date) return false;
$year=0+substr($date,0,4);
$month=0+substr($date,5,2);
$day=0+substr($date,8,2);
$t=0;
$d=date("d");
$m=date("m");
$y=date("Y");
$age=$y-$year;

if ($m<$month) $t=-1;
else if ($m==$month) if ($d<$day) $t=-1;

return ($age+$t);
}

this funktion has got a little bug:
On Line 12 and 13...
Bugfix:
12 if ($month<$m) $t=-1;
13 else if ($m==$month AND $day<$d) $t=-1;
you NOSPAM don't need 2 know ETC
24-Mar-2003 01:17
EXCEL DATES TO UNIX TIMESTAMPS
----------------------------

I get a lot of dates which are sent to me in those dastardly Excel spreadsheet things. For example, the date 15 April 1976, Excel stores as 27865.

I convert these to UNIX timestamps using the little function below.

<?
function xl2timestamp($xl_date)
{
$timestamp = ($xl - 25569) * 86400;
return $timestamp;
}
?>
garyc at earthling dot net
19-Mar-2003 02:08
I needed to calculate the week number from a given date and vice versa, where the week starts with a Monday and the first week of a year may begin the year before, if the year begins in the middle of the week (Tue-Sun). This is the way weekly magazines calculate their issue numbers.

Here are two functions that do exactly that:

Hope somebody finds this useful.

Gary

/*  w e e k n u m b e r  -------------------------------------- //
weeknumber returns a week number from a given date (>1970, <2030)
Wed, 2003-01-01 is in week 1
Mon, 2003-01-06 is in week 2
Wed, 2003-12-31 is in week 53, next years first week
Be careful, there are years with 53 weeks.
// ------------------------------------------------------------ */

function weeknumber ($y, $m, $d) {
   $wn = strftime("%W",mktime(0,0,0,$m,$d,$y));
   $wn += 0; # wn might be a string value
   $firstdayofyear = getdate(mktime(0,0,0,1,1,$y));
   if ($firstdayofyear["wday"] != 1)    # if 1/1 is not a Monday, add 1
       $wn += 1;
   return ($wn);
}    # function weeknumber

/*  d a t e f r o m w e e k  ---------------------------------- //
From a weeknumber, calculates the corresponding date
Input: Year, weeknumber and day offset
Output: Exact date in an associative (named) array
2003, 12, 0: 2003-03-17 (a Monday)
1995,  53, 2: 1995-12-xx
...
// ------------------------------------------------------------ */

function datefromweek ($y, $w, $o) {

   $days = ($w - 1) * 7 + $o;

   $firstdayofyear = getdate(mktime(0,0,0,1,1,$y));
   if ($firstdayofyear["wday"] == 0) $firstdayofyear["wday"] += 7;
# in getdate, Sunday is 0 instead of 7
   $firstmonday = getdate(mktime(0,0,0,1,1-$firstdayofyear["wday"]+1,$y));
   $calcdate = getdate(mktime(0,0,0,$firstmonday["mon"], $firstmonday["mday"]+$days,$firstmonday["year"]));

   $date["year"] = $calcdate["year"];
   $date["month"] = $calcdate["mon"];
   $date["day"] = $calcdate["mday"];

   return ($date);

}    # function datefromweek
balin
16-Feb-2003 07:23
this function count days between $start and $end dates in mysql format (yyyy-mm-dd)
if one of paramters is 0000-00-00 will return 0
$start date must be less then $end
<?
//For Count Days
function count_days($start, $end)
{
   if( $start != '0000-00-00' and $end != '0000-00-00' )
   {
       $timestamp_start = strtotime($start);
       $timestamp_end = strtotime($end);
       if( $timestamp_start >= $timestamp_end ) return 0;
       $start_year = date("Y",$timestamp_start);
       $end_year = date("Y", $timestamp_end);
       $num_days_start = date("z",strtotime($start));
       $num_days_end = date("z", strtotime($end));
       $num_days = 0;
       $i = 0;
       if( $end_year > $start_year )
       {
           while( $i < ( $end_year - $start_year ) )
           {
             $num_days = $num_days + date("z", strtotime(($start_year + $i)."-12-31"));
             $i++;
           }
         }
         return ( $num_days_end + $num_days ) - $num_days_start;
   }
   else
   {
         return 0;
     }
}
?>
jlim at natsoft dot com dot my
26-Jan-2003 07:28
For a date() function that supports dates outside the range 1901 and 2038 (by using floats when needed) see adodb_date( ) in

http://php.weblogs.com/adodb_date_time_library
zan at stargeek dot com
24-Jan-2003 03:49
an update to my earlier webcalendar funciton this is a class that uses a table full of start and end dates to generate a webcalendar http://www.stargeek.com/scripts.php?script=11&cat=blog
brighn (a) yahoo (.) com
03-Jan-2003 03:46
I needed a function that determined the last Sunday of the month. Since it's made for the website's "next meeting" announcement, it goes based on the system clock; also, if today is between Sunday and the end of the month, it figures out the last Sunday of *next* month. lastsunday() takes no arguments and returns the date as a string in the form "January 26, 2003". I could probably have streamlined this quite a bit, but at least it's transparent code. =)

  /* The two functions calculate when the next meeting will
     be, based on the assumption that the meeting will be on
     the last Sunday of the month. */ 

  function getlast($mon, $year) {
   $daysinmonth = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
   $days = $daysinmonth[$mon-1];
   if ($mon == 2 && ($year % 4) == 0 && (($year % 100) != 0 ||
   ($year % 400) == 0)) $days++;
   if ($mon == 2 && ($year % 4) == 0 && ($year % 1000) != 0) $days++;
   $lastday = getdate(mktime(0,0,0,$mon,$days,$year));
   $wday = $lastday['wday'];
   return getdate(mktime(0,0,0,$mon,$days-$wday,$year));
  }

  function lastsunday() {
   $today = getdate();
   $mon = $today['mon'];
   $year = $today['year'];
   $mday = $today['mday'];
   $lastsun = getlast($mon, $year);
   $sunday = $lastsun['mday'];
   if ($sunday < $mday) {
     $mon++;
     if ($mon = 13) {
       $mon = 1;
       $year++;
     }
     $lastsun = getlast($mon, $year);
     $sunday = $lastsun['mday'];
   }
   $nextmeeting = getdate(mktime(0,0,0,$mon,$sunday,$year));
   $month = $nextmeeting['month'];
   $mday = $nextmeeting['mday'];
   $year = $nextmeeting['year'];
   return "$month $mday, $year";
  }
visualmind at php dot net
25-Dec-2002 06:49
Here's a new function for Hejri (Hijri) date conversion, It has a better flawless calculation than the previous posted function and it's implemented to be an official alternative for the php DATE function which returns Arabic Translated date and optionally Hejri converted.
Note: to view arabic titles correctly change view-encoding to Arabic-Windows (windows-1256)

function arabicDate($format, $timestamp) {
   /*
       written by Salah Faya (visualmind@php.net) http://www.php4arab.info/scripts/arabicDate
         $format:
               [*]hj|ar|en:[jdl][Fmn][Yy][Aa]  (php.date function handles the rest chars)
               * will add <span dir=rtl lang=ar-sa>..</span>
           examples:
               echo arabicDate('hj:l d-F-Y هـ', time()); 
               echo arabicDate('ar:l d/F - h:iA', time());
   */
   $format=trim($format);
   if (substr($format,0,1)=='*') {
               $use_span=true;
       $format=substr($format,1);
       } else $use_span=false;
   $type=substr($format,0,3);

   $arDay = array("Sat"=>"السبت", "Sun"=>"الأحد", "Mon"=>"الإثنين", "Tue"=>"الثلاثاء",
 "Wed"=>"الأربعاء", "Thu"=>"الخميس", "Fri"=>"الجمعة");
   $ampm=array('am'=>'صباحا','pm'=>'مساء');
   list($d,$m,$y,$dayname,$monthname,$am)=explode(' ',date('d m Y D M a', $timestamp));
   if ($type=='hj:') {
       if (($y>1582)||(($y==1582)&&($m>10))||(($y==1582)&&($m==10)&&($d>14))) {
           $jd=ard_int((1461*($y+4800+ard_int(($m-14)/12)))/4);
           $jd+=ard_int((367*($m-2-12*(ard_int(($m-14)/12))))/12);
           $jd-=ard_int((3*(ard_int(($y+4900+ard_int(($m-14)/12))/100)))/4);
           $jd+=$d-32075;
       } else    {
           $jd = 367*$y-ard_int((7*($y+5001 + ard_int(($m-9)/7)))/4) + ard_int((275*$m)/9)+$d+1729777;
       }
       $l=$jd-1948440+10632;
       $n=ard_int(($l-1)/10631);
       $l=$l-10631*$n+355;  // Correction: 355 instead of 354
       $j=(ard_int((10985-$l)/5316)) * (ard_int((50*$l)/17719)) + (ard_int($l/5670)) * (ard_int((43*$l)/15238));
       $l=$l-(ard_int((30-$j)/15)) * (ard_int((17719*$j)/50)) - (ard_int($j/16)) * (ard_int((15238*$j)/43))+29;
       $m=ard_int((24*$l)/709);
       $d=$l-ard_int((709*$m)/24);
       $y=30*$n+$j-30;       
       $format=substr($format,3);
       $hjMonth = array("محرم", "صفر", "ربيع أول", "ربيع ثاني",
 "جماد أول", "جماد ثاني", "رجب", "شعبان", "رمضان", "شوال", "ذو القعدة", "ذو الحجة");
       $format=str_replace('j', $d, $format);
       $format=str_replace('d', str_pad($d,2,0,STR_PAD_LEFT), $format);
       $format=str_replace('l', $arDay[$dayname], $format);
       $format=str_replace('F', $hjMonth[$m-1], $format);
       $format=str_replace('m', str_pad($m,2,0,STR_PAD_LEFT), $format);
       $format=str_replace('n', $m, $format);
       $format=str_replace('Y', $y, $format);
       $format=str_replace('y', substr($y,2), $format);
       $format=str_replace('a', substr($ampm[$am],0,1), $format);
       $format=str_replace('A', $ampm[$am], $format);
   } elseif ($type=='ar:') {
       $format=substr($format,3);
       $arMonth=array("Jan"=>"يناير", "Feb"=>"فبراير","Mar"=>"مارس", "Apr"=>"ابريل", "May"=>"مايو",
"Jun"=>"يونيو", "Jul"=>"يوليو", "Aug"=>"اغسطس", "Sep"=>"سبتمبر", "Oct"=>"اكتوبر",
 "Nov"=>"نوفمبر", "Dec"=>"ديسمبر");
       $format=str_replace('l', $arDay[$dayname], $format);
       $format=str_replace('F', $arMonth[$monthname], $format);
       $format=str_replace('a', substr($ampm[$am],0,1), $format);
       $format=str_replace('A', $ampm[$am], $format);
       }
   $date = date($format, $timestamp);
   if ($use_span) return '<span dir="rtl" lang="ar-sa">'.$date.'</span>';
   else return $date;
}

function ard_int($float) {
       return ($float < -0.0000001) ? ceil($float-0.0000001) : floor($float+0.0000001);
}
eric at nitrateNO_SPAM dot nl
08-Dec-2002 11:16
Here is a quick example of how to iterate through all days
between 2 dates (with a adjustable increment)
---------------------------------------------------------
//make time stamps from our start & end dates
$start_time = mktime(0,0,0,$start_month,$start_day,$start_year);
$end_time = mktime(0,0,0,$end_month,$end_day,$end_year);

//find the number of days between start_time & end_time
$days = ($end_time - $start_time) / (24 * 3600);
//we want to count the days including the first ..
$days++;

//select a 1 week interval ..
$inc=7; 

//find all days (actually periods since we use a increment)
for ($i=0;$i<$days;$i+=$inc)
{
  //calculate start & end of period using some magic of mktime :)
  $start_date = date("Y-m-d", mktime(0,0,0,$start_month,$start_day+$i,$start_year));
  $end_date = date("Y-m-d", mktime(0,0,0,$start_month,$start_day+$i+$inc-1,$start_year)); 
  //print it all ...
  print("Period start:" . $start_date . "\n");
  print("Period end: " . $end_date . "\n");
}
asg at ftpproxy dot org
24-Sep-2002 07:23
If you like to have the last day of the current month, try this oneliner:

$lastday = strftime ("%d.%m.%Y", (mktime (0,0,0,(date(m)+1),0,(date(Y)))));

-
nightowl at NOS-PA-M dot uk2 dot net
30-Jul-2002 04:59
I wanted to find all records in my database which match the current week (for a call-back function). I made up this function to find the start and end of the current week :

function week($curtime) {
  
   $date_array = getdate (time());
   $numdays = $date_array["wday"];
  
   $startdate = date("Y-m-d", time() - ($numdays * 24*60*60));
   $enddate = date("Y-m-d", time() + ((7 - $numdays) * 24*60*60));

   $week['start'] = $startdate;
   $week['end'] = $enddate;
  
   return $week;
  
}
mwedgwood at ILUVSPAMhotmail dot com
31-Mar-2002 08:24
In vincentv's examples, you should use gmmktime instead of mktime for portability across time zones. For example:

function DateSub($timestamp, $unit, $amount) {
// Possible $units are: "hr", "min", "sec",
//          "mon", "day", or "yr"
// $amount should be an integer
   $delta_vars = array("hr"=>0, "min"=>0,
   "sec"=>0, "mon"=>1,
   "day"=>1,"yr"=>1970);
   $delta_vars[$unit] += $amount;
   $delta = gmmktime($delta_vars["hr"],
   $delta_vars["min"],
   $delta_vars["sec"],
   $delta_vars["mon"],
   $delta_vars["day"],
   $delta_vars["yr"]);
   return $timestamp - $delta;
}
mindaugas at roventa dot lt
18-Feb-2002 09:31
Some lines about LeapYear and day count of month:

   function mod($a,$b)
   {
   $x1=(int) abs($a/$b);
   $x2=$a/$b;
   return $a-($x1*$b);   
   }   

   function IsLeapYear($dt)
   {
   $y=$dt["year"];
   $bulis=((mod($y,4)==0) && ((mod ($y,100)<>0) || (mod($y,400)==0)));
   return $bulis;
   }

   function daycount($dt)
   {
   $dc_year=$dt["year"];
   $dc_month=$dt["mon"];
   $dc_day=$dt["mday"];
   switch ($dc_month)
   {
   case  1:
   case  3:
   case  5:
   case  7:
   case  8:
   case 10:
   case 12:
           return 31;
       break;
   case  4:
   case  6:
   case  9:
   case 11:
           return 30;
       break;   
   case 2:
       if (IsLeapYear($dt)) { return 28; } else { return 29; };
       break;       
   }
   }
php-contrib at i-ps dot nospam dot net
30-Jan-2002 12:07
Someone may find this info of some use:

Rules for calculating a leap year:

1) If the year divides by 4, it is a leap year (1988, 1992, 1996 are leap years)
2) Unless it divides by 100, in which case it isn't (1900 divides by 4, but was not a leap year)
3) Unless it divides by 400, in which case it is actually a leap year afterall (So 2000 was a leap year).

In practical terms, to work out the number of days in X years, multiply X by 365.2425, rounding DOWN to the last whole number, should give you the number of days.

The result will never be more than one whole day inaccurate, as opposed to multiplying by 365, which, over more years, will create a larger and larger deficit.
vincentv at thevoid dot demon dot nl
07-Feb-2001 11:23
Some general date functions.

function sub($timestamp, $seconds,$minutes,$hours,$days,$months,$years) {
   $mytime = mktime(1+$hours,0+$minutes,0+$seconds,1+$months,1+$days,1970+$years);
   return $timestamp - $mytime;
}
function add($timestamp, $seconds,$minutes,$hours,$days,$months,$years) {
   $mytime = mktime(1+$hours,0+$minutes,0+$seconds,1+$months,1+$days,1970+$years);
   return $timestamp + $mytime;
}
function dayOfWeek($timestamp) {
   return intval(strftime("%w",$timestamp));
}
function daysInMonth($timestamp) {
   $timepieces    = getdate($timestamp);
   $thisYear          = $timepieces["year"];
   $thisMonth        = $timepieces["mon"];
  
   for($thisDay=1;checkdate($thisMonth,$thisDay,$thisYear);$thisDay++);
  
   return $thisDay;
}
function firstDayOfMonth($timestamp) {
   $timepieces        = getdate($timestamp);
   return mktime(    $timepieces["hours"],
                     $timepieces["minutes"],
                   $timepieces["seconds"],
                   $timepieces["mon"],
                   1,
                   $timepieces["year"]);
}
function monthStartWeekDay($timestamp) {
   return dayOfWeek(firstDayOfMonth($timestamp));
}
function weekDayString($weekday) {
   $myArray = Array(        0 => "Sun",
                             1 => "Mon",
                           2 => "Tue",
                           3 => "Wed",
                           4 => "Thu",
                           5 => "Fri",
                           6 => "Sat");
   return $myArray[$weekday];
}
function stripTime($timestamp) {
   $timepieces        = getdate($timestamp);
   return mktime(    0,
                     0,
                   0,
                   $timepieces["mon"],
                   $timepieces["mday"],
                   $timepieces["year"]);
}
function getDayOfYear($timestamp) {
   $timepieces        = getdate($timestamp);
   return intval($timepieces["yday"]);
}
function getYear($timestamp) {
   $timepieces        = getdate($timestamp);
   return intval($timepieces["year"]);
}
function dayDiff($timestamp1,$timestamp2) {
   $dayInYear1 = getDayOfYear($timestamp1);
   $dayInYear2 = getDayOfYear($timestamp2);
   return ((getYear($dayInYear1)*365 + $dayInYear1) -
             (getYear($dayInYear2)*365 + $dayInYear2));
}

hope they are usefull to you.

- Vincent
th at definitynet dot com
11-Jan-2001 05:00
I had some problems with dates between mySQL and PHP.  PHP had all these great date functions but I wanted to store a usable value in my database tables. In this case I was using TIMESTAMP(14)  <or 'YYYYMMDDHHMMSS'>.
This is perhaps the easiest way I have found to pull the PHP usable UNIX Datestamp from my mySQL datestamp stored in the tables:

Use the mySQL UNIX_TIMESTAMP() function in your SQL definition string. i.e.

$sql= "SELECT field1, field2, UNIX_TIMESTAMP(field3) as your_date
         FROM your_table
         WHERE field1 = '$value'";

The query will return a temp table with coulms "field1" "Field2" "your_date"

The "your_date" will be formatted in a UNIX TIMESTAMP!  Now you can use the PHP date() function to spew out nice date formats.

Sample using above $sql:
20010111002747  = Date Stored on mySQL table (TIMESTAMP(14))
979172867  = value returned as your_date in sql stmt (UNIX_TIMESTAMP)

if we use $newdate = date("F jS, Y -- g:ia", $row["your_date"]);
   --(after fetching our array from the sql results of course)--

echo "$newdate";              --Will produce:
January 11th, 2001 -- 12:27am

Hope this helps someone out there!
joey dot garcia at usa dot net
13-Nov-2000 06:13
I was trying to make a Month-At-A-Glance and I finally got it to work so I thought I'd share it too.  What you need to get this to work is the "Day Of The Week Number", i.e., Sunday=1 and the "Number Of Days in the Month".  I also used Allan Kent's Date/Time Column at PHPBuilder to get the required information.  I also added the process I used to the requried information.

Enjoy!

<html>
<head>
   <title>Month-At-A-Glance</title>
</head>
<body>
<?php
// *** These are here if you need to calculate the required values ***
// *** Reference Allan Kent's Column on Dates at PHPBuilder.com
//$thismonth =  mktime($hours, $minutes,$seconds ,$month, $day,$year);
//$firstday =  mktime($hours, $minutes,$seconds ,$month, 1,$year);
//$dayofweek=date("D",$thismonth);
//$firstdayofmonth=date("D",$firstday);
//$weekdaynum=array("Sun"=>1, "Mon"=>2, "Tue"=>3, "Wed"=>4, "Thu"=>5, "Fri"=>6, "Sat"=>7);
//$dayNumber=$weekdaynum[$dayofweek];

print "<table width=80% align=center border=1>\n";
print"<tr><th>Sun(1)</th> <th>Mon(2)</th> <th>Tue(3)</th> <th>Wed(4)</th> <th>Thu(5)</th> <th>Fri(6)</th> <th>Sat(7)</th> </tr>";
$daysinmonth=31;//For July 2000 this is 31 days
$daycount=1;
$firstdayofmonth=7;//For July 2000 this is Sat, or day 7
for ($week=1; $week <= 6; $week++){
print"<tr>\n";
   for($day=1; $day <=7; $day++){
       if( ($day >= $firstdayofmonth) || ($week >1) ){
           print"<td height=40px>";
               if ($daycount <= $daysinmonth){
                   print $daycount;
                   $daycount++;
               }
           print"&nbsp;</td>\n";
       }
       else{
           print"<td height=40px> &nbsp; </td>\n";
       }
   }
print"\n</tr>\n";
}
print"</table>";
?>
</body>
</html>
teddk at box100 dot com
08-Sep-2000 09:02
There is an an excellent article by Allan Kent on PHP date/time. The full article can be found at:
http://www.phpbuilder.net/columns/akent20000610.php3
25-Apr-2000 12:44
Regarding the postings regarding MySQL timestamps, please be aware that there are several MySQL date and time types, as documented at
http://www.mysql.com/Manual_chapter/manual_Reference.html#Date_and_time_types

So, in reference to the above posts, nic_lee's algorhythm works on the MySQL TIMESTAMP type, while jmat's function works on the MySQL DATETIME type -- they are NOT the same!
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