Date/Time 日期／时间函数

add a note User Contributed Notes

gary at gmartellino dot com
05-May-2006 01:35


here's a quick script i used to find recurring dates, it offers some flexibility in how you want to iterate though the dates



<?php



// ----------------------------------------------------------

//  Recurring dates

//  Returns an array of recurring dates

// ----------------------------------------------------------



class recur {

    

    var $endOption;        // set to either "endBy" or "endAfter" -- endby if you want to end by a date and 

                        // end after if you want to end after 'x' amount of occurrences

    var $endValue;      // set to either a date in 'xxxx-xx-xx' format or a number of occurrences

    var $start;            // set to the starting date in 'xxxx-xx-xx' format

    

    function interval($type, $spread){

        $startDate = explode("-", $this->start);

        $time = mktime(0, 0, 0, $startDate[1], $startDate[2], $startDate[0]);

            

        $dates[] = $this->start;

        

        if($this->endOption == "endAfter"){

            

            for($i = 1; $i < $this->endValue; $i++){

                $futureTime = strtotime("+$spread $type", $time);

                $dates[] = date("Y-m-d", $futureTime);

                $time = $futureTime;

            }

            

            return $dates;

        }else if($this->endOption == "endBy"){

            $endDate = explode("-", $this->endValue);

            $endTime = mktime(0, 0, 0, $endDate[1], $endDate[2], $endDate[0]);

            

            while($endTime > $time){

                $futureTime = strtotime("+$spread $type", $time);

                if($futureTime > $endTime){

                    break;

                }

                $dates[] = date("Y-m-d", $futureTime);

                $time = $futureTime;

            }

            return $dates;

        }

    }

    

}

?>

example:



<?php

include("includes/recur.class.php");



$recur = new recur();

$recur->endOption = "endBy";

$recur->endValue = '2006-12-09';

$recur->start = '2006-04-28';



print_r($recur->interval("day", 4));

?>

rugby7s at gmail dot com
08-Mar-2006 11:00


I had same problem nickaubert  had with trying to compute timestamp for a span of dates that was daylight savings compliant.



OLD CODE:

 /***********************************************

*Note - This is the old code that doesn't handle daylights savings time

***********************************************/

for($i=$start_date; $i<=$end_date; $i=($i+(24*60*60))){ 

 //--- DO something $i is timestamp

}

 



NEW CODE:

for($i=$start_date;$i<=$end_date;

$i=(mktime(0,0,0,date('n',$i),date('d',$i)+1,date('Y',$i)))){ 

 //--- DO something $i is timestamp

}

03-Mar-2006 11:50


A quick one liner to round a timestamp to the next full hour.



ie, 8:36 => 9:00, 9:02 => 10:00



$timestamp = ceil(time()/3600)*3600;

worm (zantATglazovDOTnet)
25-Jan-2006 10:44


Function for converting  RFC 2822 formatted date to timestamp

<?php



/**

 * @param  string  $date RFC 2822 formatted date

 * @return integer timestamp

 */



function Rfc2822ToTimestamp($date){

  $aMonth = array(

              "Jan"=>"1", "Feb"=>"2", "Mar"=>"3", "Apr"=>"4", "May"=>"5",

              "Jun"=>"6", "Jul"=>"7", "Aug"=>"8", "Sep"=>"9", "Oct"=>"10",

              "Nov"=>"11", "Dec"=>"12");



  list( , $day, $month, $year, $time) = explode(" ", $date);

  list($hour, $min, $sec) = explode(":", $time);

  $month = $aMonth[$month];



  return mktime($hour, $min, $sec, $month, $day, $year);

}

?>

Jeff
03-Nov-2005 11:29


Here is a somewhat simpler function for getting the number of  business days between two dates



<?php



function WorkDays( $startTime, $endTime )

{

    $workdays = 0 ;

    while( $startTime <= $endTime )

    {

        if( date('w', $startTime ) != 6 && date( 'w', $startTime) != 0 )

        {

            $workdays++ ;

        }

        $startTime += 86400 ;

    }

    return $workdays ;

}



?>

cupidomind at yahoo dot fr
15-Oct-2005 11:18


Hi I just want to say thanks a lot to the man who wrote a solution about a problem of the date-difference.



/*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.*/

rycker+phpdate at gmail dot com
05-Oct-2005 03:30


Function for converting MySQL timestamp to Datetime format



function TimestampToDatetime($Tstamp) {

    $dt[0] = substr($Tstamp,0,4);

    $dt[1] = substr($Tstamp,4,2);

    $dt[2] = substr($Tstamp,6,2);

    $tm[0] = substr($Tstamp,8,2);

    $tm[1] = substr($Tstamp,10,2);

    $tm[2] = substr($Tstamp,12,2);

    return (join($dt,"-") . " " . join($tm,":"));

}

andreencinas at yahoo dot com dot br
28-Sep-2005 08:08


//function like dateDiff Microsoft

       //not error in year Bissesto



       function dateDiff($interval,$dateTimeBegin,$dateTimeEnd) {

         //Parse about any English textual datetime

         //$dateTimeBegin, $dateTimeEnd



         $dateTimeBegin=strtotime($dateTimeBegin);

         if($dateTimeBegin === -1) {

           return("..begin date Invalid");

         }



         $dateTimeEnd=strtotime($dateTimeEnd);

         if($dateTimeEnd === -1) {

           return("..end date Invalid");

         }



         $dif=$dateTimeEnd - $dateTimeBegin;



         switch($interval) {

           case "s"://seconds

               return($dif);



           case "n"://minutes

               return(floor($dif/60)); //60s=1m



           case "h"://hours

               return(floor($dif/3600)); //3600s=1h



           case "d"://days

               return(floor($dif/86400)); //86400s=1d



           case "ww"://Week

               return(floor($dif/604800)); //604800s=1week=1semana



           case "m": //similar result "m" dateDiff Microsoft

               $monthBegin=(date("Y",$dateTimeBegin)*12)+

                 date("n",$dateTimeBegin);

               $monthEnd=(date("Y",$dateTimeEnd)*12)+

                 date("n",$dateTimeEnd);

               $monthDiff=$monthEnd-$monthBegin;

               return($monthDiff);



           case "yyyy": //similar result "yyyy" dateDiff Microsoft

               return(date("Y",$dateTimeEnd) - date("Y",$dateTimeBegin));



           default:

               return(floor($dif/86400)); //86400s=1d

         }



       }

glashio at xs4all dot nl
27-Sep-2005 03:46


Calculate Sum BusinessDays (Mon till Fri) between two date's :



<?php

function businessdays($begin, $end) {

    $rbegin = is_string($begin) ? strtotime(strval($begin)) : $begin;

    $rend = is_string($end) ? strtotime(strval($end)) : $end;

    if ($rbegin < 0 || $rend < 0)

        return 0;



    $begin = workday($rbegin, TRUE);

    $end = workday($rend, FALSE);



    if ($end < $begin) {

        $end = $begin;

        $begin = $end;

    }



    $difftime = $end - $begin;

    $diffdays = floor($difftime / (24 * 60 * 60)) + 1;



    if ($diffdays < 7) {

        $abegin = getdate($rbegin);

        $aend = getdate($rend);

        if ($diffdays == 1 && ($astart['wday'] == 0 || $astart['wday'] == 6) && ($aend['wday'] == 0 || $aend['wday'] == 6))

            return 0;

        $abegin = getdate($begin);

        $aend = getdate($end);

        $weekends = ($aend['wday'] < $abegin['wday']) ? 1 : 0;

    } else

        $weekends = floor($diffdays / 7);

    return $diffdays - ($weekends * 2);

}



function workday($date, $begindate = TRUE) {

    $adate = getdate($date);

    $day = 24 * 60 * 60;

    if ($adate['wday'] == 0) // Sunday

        $date += $begindate ? $day : -($day * 2);

    elseif ($adate['wday'] == 6) // Saterday

        $date += $begindate ? $day * 2 : -$day;

    return $date;

}

?>

Eric Z (ezsomething at hotmail)
01-Sep-2005 05:56


I was having a horrible time trying to get a good list of timezones, how to set them locally (for the user/client), and how best to keep this information. Building on the notes of this site (thanks everyone), I constructed code that should work on just about any un*x based platform.  It reads the local timezone table and gives your a nested array of the continents and regions of the file -- the natural continent sorting is even by the most populated areas (thanks Paul Eggert!).



Afterwards, all you have to do is export the timezone string with an environmental set.. which works just fine if php is running as an apache model; haven't tested it for commandline, but I suspect it's okay there, too.



<?php 

if (isset($_SESSION[PROFILE_TZOFFSET]))

        putenv('TZ='.$_SESSION[PROFILE_TZOFFSET]);

?>



Here's how to load the timezones... the nested array makes it easy to insert into html lists or other well-behaved objects.



<?php

    function getTimezoneData() {

      //EricZ - 9/1/05 - free to use, keep the comments :)

      $zoneNames = array();



      // -- first part, gather all of the zone data

      $zoneSource = '/usr/share/zoneinfo/zone.tab';

      $zoneHandle = fopen($zoneSource, "r");

      if (!$zoneHandle) return NULL;                  //bad file, abort now

      while (!feof($zoneHandle)) {

        $zoneLine = ltrim(fgets($zoneHandle, 4096));

        if ($zoneLine[0]=='#')  continue;           //skip comments

         //Columns...

         // 1.  ISO 3166 2-character country code.

         // 2.  Latitude and longitude of the zone's principal location

         // 3.  Zone name used in value of TZ environment variable.

         // 4.  Comments; present if and only if country has multiple rows.

        $zoneParts = explode("\t",$zoneLine);       //grab parts

        if (count($zoneParts) < 3) continue;       //erroneous line!

        $nameParts = explode('/', $zoneParts[2], 2);   //grab country/name

        $zoneKey = $nameParts[0];                   //country or area



        $insertArray = &$zoneNames;                 //where to insert?

        if (count($nameParts) > 1) {                //area/populous

          if (!isset($zoneNames[$zoneKey]))         //not set before

            $zoneNames[$zoneKey] = array();

          $insertArray = &$zoneNames[$zoneKey];     //grab sub (country)

          $zoneKey = trim($nameParts[1]);           //grab correct key

        }

        $zoneKey = preg_replace('/[_]/',' ', $zoneKey);

        $insertArray[$zoneKey] = trim($zoneParts[2]); //actually set data

      }                                             //end while not eof

      fclose($zoneHandle);

      return $zoneNames;

    }

?>

daniel at globalnetstudios dot com
09-Jun-2005 02:49


This dateDiff() function can take in just about any timestamp, including UNIX timestamps and anything that is accepted by strtotime(). It returns an array with the ability to split the result a couple different ways. I built this function to suffice any datediff needs I had. Hope it helps others too.



<?php

  /********* dateDiff() function **********

   * returns Array of Int values for difference between two dates

   * $date1 > $date2 --> positive integers are returned

   * $date1 < $date2 --> negative integers are returned

   *

   * $split recognizes the following:

   *   'yw' = splits up years, weeks and days (default)

   *   'y'  = splits up years and days

   *   'w'  = splits up weeks and days

   *   'd'  = total days

   *

   * examples:

   *   $dif1 = dateDiff() or dateDiff('yw')

   *   $dif2 = dateDiff('y')

   *   $dif3 = dateDiff('w')

   *   $dif4 = dateDiff('d')

   *

   * assuming dateDiff returned 853 days, the above

   * examples would have a print_r output of:

   *   $dif1 == Array( [y] => 2 [w] => 17 [d] => 4 )

   *   $dif2 == Array( [y] => 2 [d] => 123 )

   *   $dif3 == Array( [w] => 121 [d] => 6 )

   *   $dif4 == Array( [d] => 847 )

   *

   * note: [h] (hours), [m] (minutes), [s] (seconds) are always returned as elements of the Array

   */

  function dateDiff($dt1, $dt2, $split='yw') {

    $date1 = (strtotime($dt1) != -1) ? strtotime($dt1) : $dt1;

    $date2 = (strtotime($dt2) != -1) ? strtotime($dt2) : $dt2;

    $dtDiff = $date1 - $date2;

    $totalDays = intval($dtDiff/(24*60*60));

    $totalSecs = $dtDiff-($totalDays*24*60*60);

    $dif['h'] = $h = intval($totalSecs/(60*60));

    $dif['m'] = $m = intval(($totalSecs-($h*60*60))/60);

    $dif['s'] = $totalSecs-($h*60*60)-($m*60);

    // set up array as necessary

    switch($split) {

    case 'yw': # split years-weeks-days

      $dif['y'] = $y = intval($totalDays/365);

      $dif['w'] = $w = intval(($totalDays-($y*365))/7);

      $dif['d'] = $totalDays-($y*365)-($w*7);

      break;

    case 'y': # split years-days

      $dif['y'] = $y = intval($totalDays/365);

      $dif['d'] = $totalDays-($y*365);

      break;

    case 'w': # split weeks-days

      $dif['w'] = $w = intval($totalDays/7);

      $dif['d'] = $totalDays-($w*7);

      break;

    case 'd': # don't split -- total days

      $dif['d'] = $totalDays;

      break;

    default:

      die("Error in dateDiff(). Unrecognized \$split parameter. Valid values are 'yw', 'y', 'w', 'd'. Default is 'yw'.");

    }

    return $dif;

  }

?>

mail at completeideas dot com
07-Jun-2005 04:55


For those who are using pre MYSQL 4.1.1, you can use:



TO_DAYS([Date Value 1])-TO_DAYS([Date Value 2])



For the same result as:



DATEDIFF([Date Value 1],[Date Value 2])

r00t_ at mail dot ru
06-May-2005 03:33


Function generate one month calendar like



February 

Mon Tue Wed Thu Fri Sat Sun 

               1  2   3   4 

   5   6   7     8   9    10  11 

 12  13   14   15   16  17 18 

 19  20   21   22   23  24 25 

 26  27   28 



(default in russian locale)



<?php



$year = (int)$_GET["year"];

$month = (int)$_GET["month"];



draw_month_cal($year, $month);



function draw_month_cal($year, $month, $locale = array ('ru_RU.CP1251', 'rus_RUS.1251')) 

{

    if (checkdate($month, 1, $year) && setlocale (LC_TIME, $locale)) {

    

        if (!$day = date("w", $f_day = mktime(0, 0, 0, $month, 1, $year))) 

            $day = 7; // Mon first, Sun last

        

        print "<table border=0><tr><th colspan=7>" . strftime("%B", $f_day) . "</td></tr><tr>"; // Month

        

        for ($i = 8; --$i;) 

            print "<th>" . strftime("%a", mktime(0, 0, 0, $month, 16 - $i - $day, $year)) . "</th>"; // Mon Tue Wed Thu Fri Sat Sun  

            

        print "</tr><tr>" . str_repeat("<td></td>", --$day); // Empty cells

        

        while (checkdate($month, ++$i, $year)) { // $i==0 after for :-)

            print "<td>$i</td>";

            if (!(++$day % 7)) print "</tr><tr>"; // next line after Sun

        }

        print "</tr></table>";

    } 

} 



?>

info at programare dot org
06-May-2005 01:34


A simple DateAdd() function:



function DateAdd($v,$d=null , $f="d/m/Y"){ 

  $d=($d?$d:date("Y-m-d")); 

  return date($f,strtotime($v." days",strtotime($d))); 

}



Then use it:



echo DateAdd(2);  // 2 days after

echo DateAdd(-2,0,"Y-m-d");  // 2 days before with gigen format

echo DateAdd(3,"01/01/2000");  // 3 days after given date

datavortex at gmail dot com
19-Mar-2005 07:19


This is a litttle function I cobbled together from my own code, and snippets from this site to calculate the difference between two datetimes without having to confine it to simply one interval.  This will tell you how many weeks, days, hours, minutes, and seconds there are between the given datetimes, and also makes a little English string you can use.



This could easily be expanded to include months, and years, but I didn't want to have to deal with any of the leap year and variable month length stuff.



<?

function dateDiff($dateTimeBegin,$dateTimeEnd) {

  $dateTimeBegin =strtotime($dateTimeBegin);

  $dateTimeEnd   =strtotime($dateTimeEnd);



  if($dateTimeEnd === -1 || $dateTimeBegin === -1) {

    # error condition

    return false;

  }



  $diff = $dateTimeEnd - $dateTimeBegin;



  if ($diff < 0) {

    # error condition

    return false;

  }



  $weeks = $days = $hours = $minutes = $seconds = 0; # initialize vars



  if($diff % 604800 > 0) {

    $rest1   = $diff % 604800;

    $weeks   = ($diff - $rest1) / 604800; # seconds a week

    if($rest1 % 86400 > 0) {

      $rest2 = ($rest1 % 86400);

      $days  = ($rest1 - $rest2) / 86400; # seconds a day

      if( $rest2 % 3600 > 0 ) {

        $rest3 = ($rest2 % 3600);

        $hours = ($rest2 - $rest3) / 3600; # seconds an hour

        if( $rest3 % 60 > 0 ) {

          $seconds = ($rest3 % 60);

          $minutes = ($rest3 - $seconds) / 60;  # seconds a minute

        } else {

          $minutes = $rest3 / 60;

        }

      } else {

        $hours = $rest2 / 3600;

      }

    } else {

      $days = $rest1/ 86400;

    }

  }else {

    $weeks = $diff / 604800;

  }



  $string = array();

  if($weeks > 1) {

    $string[]  = "$weeks weeks";

  } elseif ($weeks == 1) {

    $string[]  = "a week";

  }

  if($days > 1) {

    $string[] = "$days days";

  } elseif($days == 1) {

    $string[] = "a day";

  }

  if($hours > 1) {

    $string[] = "$hours hours";

  } elseif ($hours == 1) {

    $string[] = "an hour";

  }

  if($minutes > 1) {

    $string[] = "$minutes minutes";

  } elseif ($minutes == 1) {

    $string[] = "a minute";

  }

  if($seconds > 1) {

    $string[] = "$seconds seconds";

  } elseif($seconds == 1) {

    $string[] = "a second";

  }



  # join together all the strings in the array above except the last element

  $text  = join(', ', array_slice($string,0,sizeof($string)-1)) . ", and ";

  $text .= array_pop($string);  # put the last one on after the and

  

  return array($text, $weeks, $days, $hours, $minutes, $seconds);

?>

JMPZ art JMPZ dort ORG
04-Mar-2005 12:31


If you are dealing with a date in a database, you could just use the mysql function DATEDIFF(expr1,expr2) To calculate the difference without big bulky php functions.

andreencinas at yahoo dot com dot br
19-Jan-2005 12:56


//function like dateDiff Microsoft

       //bug update for previous



       function dateDiff($interval,$dateTimeBegin,$dateTimeEnd) {

         //Parse about any English textual datetime

         //$dateTimeBegin, $dateTimeEnd



         $dateTimeBegin=strtotime($dateTimeBegin);

         if($dateTimeBegin === -1) {

           return("..begin date Invalid");

          }



         $dateTimeEnd=strtotime($dateTimeEnd);

         if($dateTimeEnd === -1) {

           return("..end date Invalid");

          }



         $dif=$dateTimeEnd - $dateTimeBegin;



         switch($interval) {

           case "s"://seconds

                return($dif);



           case "n"://minutes

                return(floor($dif/60)); //60s=1m



           case "h"://hours

                return(floor($dif/3600)); //3600s=1h



           case "d"://days

                return(floor($dif/86400)); //86400s=1d



           case "ww"://Week

                return(floor($dif/604800)); //604800s=1week=1semana



           case "m": //similar result "m" dateDiff Microsoft

                $monthBegin=(date("Y",$dateTimeBegin)*12)+

                  date("n",$dateTimeBegin);

                $monthEnd=(date("Y",$dateTimeEnd)*12)+

                  date("n",$dateTimeEnd);

                $monthDiff=$monthEnd-$monthBegin;

                return($monthDiff);



           case "yyyy": //similar result "yyyy" dateDiff Microsoft

                return(date("Y",$dateTimeEnd) - date("Y",$dateTimeBegin));



           default:

                return(floor($dif/86400)); //86400s=1d

          }



        }

Elizalde Baguinon
08-Jan-2005 10:46


I evaluated the modified version of Xiven's datediff (below) and I saw some errors. I switched the lines of getting the seconds and the formatting of date. I was testing the datediff() function with a "d" interval. Here I added my test code.



$dateA = "2004-12-31";

$dateB = "2005-01-01";



function datediff($interval, $date1, $date2) {

   // Function roughly equivalent to the ASP "DateDiff" function

  

   /* Get the seconds first */

   $seconds = strtotime($date2) - strtotime($date1);



   $date1=date("Y-m-d", strtotime($date1));

   $date2=date("Y-m-d",strtotime($date2));

  

   switch($interval) {

       case "y":

           list($year1, $month1, $day1) = split('-', $date1);

           list($year2, $month2, $day2) = split('-', $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":

           /* parses the year, month and days. split() was replaced with explode(), PHP Manual says it's faster */

           list($year1, $month1, $day1) = explode('-', $date1);

           list($year2, $month2, $day2) = explode('-',$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 the +ve integer only

   if ($diff<0){

      $diff=0-$diff;

   }

   return $diff;

}



echo "x: $dateA<br>";

echo "y: $dateB<br>";

echo "<br>";



echo datediff ("d",$dateA, $dateB);

Ruby
07-Jan-2005 12:09


just modified from Xiven



function datediff($interval, $date1, $date2) {

   // Function roughly equivalent to the ASP "DateDiff" function

   

   //set the date format first

   $date1= date("Y-m-d", strtotime($date1));

   $date2= date("Y-m-d",strtotime($date2));

   

   $seconds = $date2 - $date1;

   

   switch($interval) {

       case "y":

           list($year1, $month1, $day1) = split('-', $date1);

           list($year2, $month2, $day2) = split('-', $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('-', $date1);

           list($year2, $month2, $day2) = split('-',$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 the +ve integer only

   if ($diff <0)

   {

           $diff= 0-$diff;

   }

   return $diff;

}

mincklerstraat at softhome dot net
11-Oct-2004 04:43


Before you get too advanced using date functions, be sure also to see the calendar functions at http://www.php.net/manual/en/ref.calendar.php .

charles at etherscapes dot com
04-Jun-2004 07:54


There are two dates that I know of that produce an incorrect result for the date functions above: 2004-04-04 and 2004-04-05. The days difference is zero instead of one.

jens at jebecs dot de
03-Jun-2004 07:29


There is an error in vincentv's post from 07-Feb-2001 11:23:

In function dayDiff(..) the return statement must be replaced by:

<?

return ( (getYear($timestamp1)*365 + $dayInYear1) -

         (getYear($timestamp2)*365 + $dayInYear2) );

?>

nickaubert at america's biggest isp dot com
13-Apr-2004 04:13


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 03:06


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
21-Feb-2004 02:02


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 08:58


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
26-Jan-2004 05:12


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
21-Dec-2003 02:40


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
20-Nov-2003 05:56


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 10:30


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 09:09


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
30-Aug-2003 04:40


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 11:01


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 07:37


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 11:17


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 12:08


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 05:23


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 05:28


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
25-Jan-2003 01:49


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 01:46


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 04:49


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 ', 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"=>"", "Sun"=>"", "Mon"=>"", "Tue"=>"",


 "Wed"=>"", "Thu"=>"", "Fri"=>"");


    $ampm=array('am'=>'','pm'=>''); 


    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("", "", " ", " ",


 " ", " ", "", "", "", "", " ", " "); 


        $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"=>"", "Feb"=>"","Mar"=>"", "Apr"=>"", "May"=>"", 


"Jun"=>"", "Jul"=>"", "Aug"=>"", "Sep"=>"", "Oct"=>"",


 "Nov"=>"", "Dec"=>"");


        $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
09-Dec-2002 09:16


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
25-Sep-2002 04:23


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
31-Jul-2002 01:59


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
01-Apr-2002 05:24


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 07:31


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 10:07


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
08-Feb-2001 09:23


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
12-Jan-2001 03:00


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
14-Nov-2000 04:13


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 06:02


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

add a note

XXII. Date/Time 日期／时间函数

简介

需求

安装

运行时配置

运行时配置

资源类型

预定义常量