It seems mktime() doesn't return negative timestamps on Linux systems with a version of glibc <= 2.3.3.
mktime
(PHP 4, PHP 5)
mktime — Retourne le timestamp UNIX d'une date
Description
$hour = date("H")
[, int $minute = date("i")
[, int $second = date("s")
[, int $month = date("n")
[, int $day = date("j")
[, int $year = date("Y")
[, int $is_dst = -1
]]]]]]] )mktime() retourne un timestamp UNIX correspondant aux arguments fournis. Ce timestamp est un entier long, contenant le nombre de secondes entre le début de l'époque UNIX (1er Janvier 1970 00:00:00 GMT) et le temps spécifié.
Les arguments peuvent être omis, de droite à gauche, et tous les arguments manquants sont utilisés avec la valeur courante de l'heure et du jour.
Notes
Note:
Depuis PHP 5.1, lorsqu'appelée sans argument, la fonction mktime() émet une alerte de type
E_STRICT: utilisez la fonction time() à la place.
Liste de paramètres
-
hour -
Le nombre d'heures depuis le début de la journée fixée par les paramètres
month,dayetyear. Les valeurs négatives font références aux heures avant minuit du jour en question. Les valeurs supérieures à 23 font références aux heures associées pour le(s) jour(s) suivant(s). -
minute -
Le nombre de minutes depuis le début de l'heure
hour. Les valeurs négatives font références aux minutes de l'heure précédente. Les valeurs supérieures à 59 font références aux minutes associées pour l'(les) heure(s) suivante(s). -
second -
Le nombre de secondes depuis le début de la minute
minute. Les valeurs négatives font références aux secondes de la minute précédente. Les valeurs supérieures à 59 font références aux secondes associées à la(les) minute(s) suivante(s). -
month -
Le nombre de mois depuis la fin de l'année précédente. Les valeurs comprises entre 1 et 12 font références aux mois du calendrier normal de l'année en question. Les valeurs inférieures à 1 (y compris les valeurs négatives) font références aux mois de l'année précédente dans l'ordre inverse, aussi, 0 correspond à décembre, -1 à novembre, etc. Les valeurs supérieures à 12 font références au mois correspondant dans l'(les) année(s) suivante(s).
-
day -
Le nombre de jours depuis la fin du mois précédent. Les valeurs comprises entre 1 et 28, 29, 30, 31 (suivant le mois) font références aux jours normaux dans le mois courant. Les valeurs inférieures à 1 (y compris les valeurs négatives) font références aux jours du mois précédent, aussi, 0 correspond au dernier jour du mois précédent, -1, le jour d'avant, etc. Les valeurs supérieures au nombre de jours du mois courant font références aux jours correspondants du(des) mois suivant(s).
-
year -
L'année, peut être sur deux ou quatre chiffres, avec des valeurs allant de 0 à 69, correspondant au valeur 2000 à 2069 et 70 à 100, correspondant au valeur 1970 à 2000. Sur les systèmes où time_t un entier signé sur 32bits, ce qui est le plus courant de nos jours, la période valide pour
yearest quelque part près de 1901 et 2038. Cependant, avant PHP 5.1.0, cette intervalle était limitée de 1970 à 2038 sur quelques systèmes (i.e. Windows). -
is_dst -
Ce paramètre peut être mis à 1 si l'heure d'hiver est appliquée (DST), 0 si elle ne l'est pas, et -1 (par défaut) si on ne sait pas. Si l'on ne sait pas, PHP tente de le traiter lui-même. Ceci peut occasionner des résultats inattendus (mais néanmoins correct). Quelques temps sont invalides si DST est activé sur les systèmes où PHP fonctionne ou
is_distest défini à 1. Si DST est activé e.g. 2:00, tous les temps entre 2:00 et 3:00 sont invalides et la fonction mktime() retourne une valeur indéfinie (généralement une valeur négative). Quelques systèmes (e.g. Solaris 8) activent DST à minuit, donc, le temps 0:30 du jour lorsque DST est activé est évalué à 23:30 du jour précédent.Note:
Depuis PHP 5.1.0, ce paramètre est obsolète. Comme résultat, le nouveau gestionnaire de fuseau horaire doit être utilisé à la place.
Valeurs de retour
mktime() retourne un timestamp Unix des arguments donnés.
Si les arguments ne sont pas valides, la fonction retournera FALSE (avant
PHP 5.1, elle retournait -1).
Erreurs / Exceptions
Chaque appel à une fonction date/heure générera un message de type
E_NOTICE si le fuseau horaire n'est pas valide,
et/ou un message de type E_STRICT
ou E_WARNING si vous
utilisez la configuration du système ou la variable d'environnement
TZ. Voir aussi date_default_timezone_set()
Historique
| Version | Description |
|---|---|
| 5.3.0 |
mktime() lance maintenant une alerte de type
E_DEPRECATED si le paramètre
is_dst est utilisé.
|
| 5.1.0 |
Le paramètre is_dst est obsolète. Fait que la fonction
retourne FALSE en cas d'erreur, au lieu de -1.
La fonction a été modifiée pour accepter la valeur zéro comme
année, mois ou bien jour.
|
| 5.1.0 |
Lorsqu'appelée sans argument, la fonction mktime() émet
une alerte de type E_STRICT. Utilisez la fonction
time() à la place.
|
| 5.1.0 |
Émet un message de type |
Exemples
Exemple #1 Exemple simple avec mktime()
<?php
// Configuration du fuseau horaire. Disponible depuis PHP 5.1
date_default_timezone_set('UTC');
// Affiche : July 1, 2000 est un Saturday
echo "July 1, 2000 est un " . date("l", mktime(0, 0, 0, 7, 1, 2000));
// Affiche quelque chose comme : 2006-04-05T01:02:03+00:00
echo date('c', mktime(1, 2, 3, 4, 5, 2006));
?>
Exemple #2 Exemple avec mktime()
mktime() est pratique pour faire des calculs de dates et des validations, car elle va automatiquement corriger les valeurs invalides. Par exemple, toutes les lignes suivantes vont retourner la même date : "Jan-01-1998".
<?php
echo date("M-d-Y", mktime(0, 0, 0, 12, 32, 1997));
echo date("M-d-Y", mktime(0, 0, 0, 13, 1, 1997));
echo date("M-d-Y", mktime(0, 0, 0, 1, 1, 1998));
echo date("M-d-Y", mktime(0, 0, 0, 1, 1, 98));
?>
Exemple #3 Dernier jour d'un mois
Le dernier jour d'un mois peut être décrit comme le jour "0" du mois suivant, et non pas le jour -1. Les deux exemples suivants vont donner : "Le dernier jour de Février 2000 est: 29".
<?php
$lastday = mktime(0, 0, 0, 3, 0, 2000);
echo strftime("Le dernier jour de Fevrier 2000 est : %d", $lastday);
$lastday = mktime(0, 0, 0, 4, -31, 2000);
echo strftime("Le dernier jour de Fevrier 2000 est : %d", $lastday);
?>
Notes
Avant PHP 5.1.0, les valeurs négatives des timestamp ne sont pas supportées sous toutes les versions actuelles de Microsoft Windows. De ce fait, l'intervalle valide pour les années est de 1970 à 2038, inclus.
Voir aussi
- checkdate() - Valide une date grégorienne
- gmmktime() - Retourne le timestamp UNIX d'une date GMT
- date() - Formate une date/heure locale
- time() - Retourne le timestamp UNIX actuel
Add (and subtract) unixtime:
<?php
function utime_add($unixtime, $hr=0, $min=0, $sec=0, $mon=0, $day=0, $yr=0) {
$dt = localtime($unixtime, true);
$unixnewtime = mktime(
$dt['tm_hour']+$hr, $dt['tm_min']+$min, $dt['tm_sec']+$sec,
$dt['tm_mon']+1+$mon, $dt['tm_mday']+$day, $dt['tm_year']+1900+$yr);
return $unixnewtime;
}
?>
Just a small thing to think about if you are only trying to pull the month out using mktime and date. Make sure you place a 1 into day field. Otherwise you will get incorrect dates when a month is followed by a month with less days when the day of the current month is higher then the max day of the month you are trying to find.. (Such as today being Jan 30th and trying to find the month Feb.)
The maximum possible date accepted by mktime() and gmmktime() is dependent on the current location time zone.
For example, the 32-bit timestamp overflow occurs at 2038-01-19T03:14:08+0000Z. But if you're in a UTC -0500 time zone (such as EST in North America), the maximum accepted time before overflow (for older PHP versions on Windows) is 2038-01-18T22:14:07-0500Z, regardless of whether you're passing it to mktime() or gmmktime().
Finding out the number of days in a given month and year, accounting for leap years when February has more than 28 days.
<?php
function days_in_month($year, $month) {
return( date( "t", mktime( 0, 0, 0, $month, 1, $year) ) );
}
?>
Hope it helps a soul out there.
I was using the following to get a list of month names.
for ($i=1; $i<13; $i++) {
echo date('F', mktime(0,0,0,$i) . ",";
}
Normally this outputs -
January,February,March,April,May,June,July,August,
September,October,November,December
However if today's date is the 31st you get instead:
January,March,March,May,May,July,July,August,October,
October,December,December
Why? Because Feb,Apr,June,Sept, and Nov don't have 31 days!
The fix, add the 5th parameter, don't let the day of month default to today's date:
echo date('F', mktime(0,0,0,$i,1) . ",";
You cannot simply subtract or add month VARs using mktime to obtain previous or next months as suggested in previous user comments (at least not with a DD > 28 anyway).
If the date is 03-31-2007, the following yeilds March as a previous month. Not what you wanted.
<?php
$dateMinusOneMonth = mktime(0, 0, 0, (3-1), 31, 2007 );
$lastmonth = date("n | F", $dateMinusOneMonth);
echo $lastmonth; //---> 3 | March
?>
mktime correctly gives you back the 3rd of March if you subtract 1 month from March 31 (there are only 28 days in Feb 07).
If you are just looking to do month and year arithmetic using mktime, you can use general days like 1 or 28 to do stuff like this:
<?php
$d_daysinmonth = date('t', mktime(0,0,0,$myMonth,1,$myYear)); // how many days in month
$d_year = date('Y', mktime(0,0,0,$myMonth,1,$myYear)); // year
$d_isleapyear = date('L', mktime(0,0,0,$myMonth,1,$myYear)); // is YYYY a leapyear?
$d_firstdow = date('w', mktime(0,0,0,$myMonth,'1',$myYear)); // FIRST falls on what day of week (0-6)
$d_firstname = date('l', mktime(0,0,0,$myMonth,'1',$myYear)); // FIRST falls on what day of week Full Name
$d_month = date('n', mktime(0,0,0,$myMonth,28,$myYear)); // month of year (1-12)
$d_monthname = date('F', mktime(0,0,0,$myMonth,28,$myYear)); // Month Long name (July)
$d_month_previous = date('n', mktime(0,0,0,($myMonth-1),28,$myYear)); // PREVIOUS month of year (1-12)
$d_monthname_previous = date('F', mktime(0,0,0,($myMonth-1),28,$myYear)); // PREVIOUS Month Long name (July)
$d_month_next = date('n', mktime(0,0,0,($myMonth+1),28,$myYear)); // NEXT month of year (1-12)
$d_monthname_next = date('F', mktime(0,0,0,($myMonth+1),28,$myYear)); // NEXT Month Long name (July)
$d_year_previous = date('Y', mktime(0,0,0,$myMonth,28,($myYear-1))); // PREVIOUS year
$d_year_next = date('Y', mktime(0,0,0,$myMonth,28,($myYear+1))); // NEXT year
$d_weeksleft = (52 - $d_weekofyear); // how many weeks left in year
$d_daysinyear = $d_isleapyear ? 366 : 365; // set correct days in year for leap years
$d_daysleft = ($d_daysinyear - $d_dayofyear); // how many days left in year
?>
There are several warnings here about using mktime() to determine a date difference because of daylight savings time. However, nobody seems to have mentioned the other obvious problem, which is leap years.
Leap years mean that any effort to use mktime() and time() to determine the age (positive or negative) of some timestamp in years will be flawed. There are some years that are 366 days long, therefore you cannot say that there is a set number of seconds per year.
Timestamps are good for determining *real* time, which is not the same thing as *human calendar* time. The Gregorian calendar is only an approximation of real time, which is tweaked with daylight savings time and leap years to make it conform more to humans' expectations of how time should or ought to work. Timestamps are not tweaked and therefore are the only authoritative way of recording in computers a proper order of succession of events, but they cannot be integrated with a Gregorian system unless you take both leap years and DST into account. Otherwise, you may get the wrong number of years when you are approaching a value of exactly X years.
As for PHP, you could still use timestamps as a way of determining age if you took into account not only DST but also whether or not each year is a leap year and adjusted your calculations accordingly. However, this could become messy and inefficient.
There is an alternative approach to calculating days given the day, month and year of the dates to be compared. Compare the years first, and then compare the month and day - if the month and day have already passed (or, if you like, if they match the current month and day), then add 1 to the total for the years.
This solution works because it stays within the Gregorian system and doesn't venture into the world of timestamps.
There is also the issue of leap seconds, but this will only arise if you literally need to get the *exact* age in seconds. In that case, of course, you would also need to verify that your timestamps are exactly correct and are not delayed by script processing time, plus you would need to determine whether your system conforms to UTC, etc. I expect this will hardly be an issue for anybody using PHP, however if you are interested there is an article on this issue on Wikipedia:
http://en.wikipedia.org/wiki/Leap_second
Please note that incrementing a date using mktime in a loop is not proper. You could do it, except that there is a far better method found in the DateTime PHP class. Look at the documentation for DateTime::modify, DateTime::add (when supported) and DateTime::sub (when supported).
Also, adding seconds to a time is, well it isn't as easy as it seems, "Hey I'll just add 3600 seconds or 86400 seconds or x seconds!". The phrase once bitten, twice shy is quite applicable with the usage of adding seconds. If you ever had to 'fix' a time by calculating midnight to add the correct number of seconds, then you are doing it wrong.
Luckily, knowing is not a requirement, because DateTime and friends exists, removing the complexity for you.
So if given a choice of
mktime($seconds, $minutes, $hours+1);
and
$datetime->modify('+1 hour');
or
$datetime->add('P1H');
I'll go with the second choice, but probably not the third, unless I was using DateInterval::createFromDateString, so that other developers knew my intent.
Proper way to convert Excel dates into PHP-friendly timestamps using mktime():
<?php
// The date 6/30/2009 is stored as 39994 in Excel
$days = 39994;
// But you must subtract 1 to get the correct timestamp
$ts = mktime(0,0,0,1,$days-1,1900);
// So, this would then match Excel's representation:
echo date("m/d/Y",$ts);
?>
Excel uses "number of days since Jan. 1, 1900" to store its dates. It also treats 1900 as a leap year when it wasn't, thus there is an extra day which must be accounted for in PHP (and the rest of the world). Subtracting 1 from Excel's number will fix this problem.
How many days have passed since the beginning of the year.... regardless of what year it is...
<?php
//Carlos Galindo
//phpmember.com
$days = floor((time()-mktime(null,null,null,1,0,date("Y")))/86400);
echo "$days days have passed";
//Good Luck
?>
to ADD or SUBSTRACT times NOTE that if you dont specify the UTC zone your result is the difference +- your server UTC delay.
if you are ina utc/GMT +1
<?php
$hours_diff = strtotime("20:00:00")-strtotime("19:00:00");
echo date('h:i', $hours_diff)." Hours";
?>
it shows: 02:00 Hours
but if you use a default UTC time:
<?php
date_default_timezone_set('UTC');
$hours_diff = strtotime("20:00:00")-strtotime("19:00:00");
echo "<br>". date('h:i', $hours_diff);
?>
it shows: 01:00 Hours.
Do remember that, counter-intuitively enough, the arguments for month and day are inversed (or middle-endian). A common mistake for Europeans seems to be to feed the date arguments in the expected order (big endian or little endian).
It's clear to see where this weird order comes from (even with the date being big endian the order for all arguments would still be mixed - it's obviously based on the American date format with the time "prefixed" to allow an easier shorthand) and why this wasn't changed (passing the values in the wrong order produces a valid, though unexpected, result in most cases), but it continues to be a source of confusion for me whenever I come back to PHP from other languages or libraries.
If you want to increment the day based on a variable when using a loop you can use this when you submit a form
1. Establish a start date and end date in two different variables
2. Get the number of days between a date
$ndays = (strtotime($_POST['edate']) - strtotime($_POST['sdate'])) / (60 * 60 * 24);
Then here is the string you slip in your loop
$nextday = date('Y-m-d', mktime(0, 0, 0, date("m", strtotime($_POST['sdate'])) , date("d", strtotime($_POST['sdate']))+ $count, date("Y", strtotime($_POST['sdate']))));
$count is incremented by the loop.
Convert Excel whacky-time to timestamp
function exceltoepoch($whackyexceltime) {
if (is_numeric($whackyexceltime)) {
// intify
$int_portion = (int)$whackyexceltime;
// get the decimals
$dec_portion = $whackyexceltime - $int_portion;
// $int portion is days since Jan 1, 1900.
$epoch = new DateTime('1900-01-01');
// remove 2 seems to be the magic number of days to remove.
$epoch->add(new DateInterval("P".($int_portion - 2)."D"));
// get the seconds that are left
$sec = ceil(86400 * $dec_portion);
// add the second to the epoch
$epoch->add(new DateInterval("PT".$sec."S"));
$ret = $epoch->getTimestamp();
unset($epoch);
//echo date("D, d M Y H:i:s", $ret) ."\n\n";
return $ret;
} else {
// probably not a whacky timestamp, lets try to guess it to
// an epoch and pray
$ts = strtotime($whackyexceltime);
//echo date("D, d M Y H:i:s", $ts)."\n\n";
return $ts;
}
}
To calculate the number of days between two dates, do not take the integer part of the difference is due to the transition to daylight saving time. We must take rounding:
<?php
function dateDiff($start, $end) {
$start_ts = strtotime($start);
$end_ts = strtotime($end);
$diff = $end_ts - $start_ts;
return round($diff / 86400);
}
?>
If you use the floor() instead of round() function, the result will be one day less if the start date is before the summer time date and the end date between the summer time date and the winter time date. This is due to the fact that the summer time date is one hour less.
Function for Convert Integer Params to Time
<?php
function getTimeByHourMinAndSec($hour=NULL, $min=NULL, $sec=NULL)
{
if(!empty($hour) && !empty($min) && !empty($sec))
{
if(is_int($hour) && is_int($min) && is_int($sec))
{
$min = $min + floor($sec/60);
$hour = $hour + floor($min/60);
$min = $min%60;
$sec = $sec%60;
return $hour.':'.$min.':'.$sec;
}
else
return 'NULL';
}
else if(!empty($hour) && !empty($min))
{
if(is_int($hour) && is_int($min))
{
$hour = $hour + floor($min/60);
$min = $min%60;
return $hour.':'.$min.':00';
}
else
return 'NULL';
}
else if(!empty($hour))
{
if(is_int($hour))
{
return $hour.':00:00';
}
else
return 'NULL';
}
else
return 'NULL';
}
?>
HTML5 form output date like 2012-10-08 converted to timestamp.
<?php
/**
* Convert html 5 output like YYYY-MM-DD to timestamp
* @param str $v date
* @return int UNIX timestamp
*
*/
function prepareDate($v) {
$t=explode("-", $v);
return ($v) ? mktime(0,0,0,$t[1],$t[2],$t[0]):false;
}
?>
Function to generate array of dates between two dates (date range array)
<?php
function dates_range($date1, $date2)
{
if ($date1<$date2)
{
$dates_range[]=$date1;
$date1=strtotime($date1);
$date2=strtotime($date2);
while ($date1!=$date2)
{
$date1=mktime(0, 0, 0, date("m", $date1), date("d", $date1)+1, date("Y", $date1));
$dates_range[]=date('Y-m-d', $date1);
}
}
return $dates_range;
}
echo '<pre>';
print_r(dates_range('2009-12-25', '2010-01-05'));
echo '</pre>';
?>
[EDIT BY danbrown AT php DOT net: Contains a bugfix submitted by (carlosbuz2 AT gmail DOT com) on 04-MAR-2011, with the following note: The first date in array is incorrect.]
One of the many problems with Daylight Saving Time / Summer Time is the ambiguity when a specified local time value can refer to two different actual times! This happens when the local time value is within the relapse range caused by the clocks being set back to proper time. (eg. if the DST/ST bias is +1 hour, and DST/ST terminates at 02:00 local time, a local time value of 01:30 occurs twice in the same day!)
Because the mktime() function only returns one value, it silently chooses whether to return the time-stamp for the first iteration or the second iteration of a specified local time within this critical range.
To get both possible time-stamps for a local time, compatible with any system locale, time zone, and applicable DST/ST rules, the following function can be used:
<?php /*><!--*/
function LocalToUT($LocalYear, $LocalMonth, $LocalMonthDay, $LocalHour24, $LocalMinute, $LocalSecond) {
/* Converts local date/time to Universal Time values. Returns both
possible UT values when local time value is within relapse range
(due to Daylight Saving Time / Summer Time termination).
Notes:
Conversion based on TZ and DST/ST rules used by mktime() function.
UT time-stamps are number of UT seconds since midnight Jan 1, 1970 UTC.
UT does not have leap seconds; a UT second is "stretched" by 2x duration
to maintain synchronization with UTC when a UTC leap second elapses.
Inputs: All inputs are numeric; $LocalHour24 is in 24-hour format.
Returns: Array:
'initial' = UT time-stamp of first occurrence of specified local date/time
'relapse' = UT time-stamp of second occurrence, when local time relapses upon DST/ST termination
*/
$UTValue = mktime($LocalHour24, $LocalMinute, $LocalSecond, $LocalMonth, $LocalMonthDay, $LocalYear);
$ReturnData = array('initial' => $UTValue, 'relapse' => $UTValue);
//Test for DST/ST transition since prev day
$Bias = $UTValue - mktime($LocalHour24, $LocalMinute, $LocalSecond, $LocalMonth, $LocalMonthDay - 1, $LocalYear) - 86400; //(-) = DST/ST commence, (+) = DST/ST terminate
if ($Bias == 0) { //No DST/ST transition detected since prev day
//Test for DST/ST transition up to next day
$Bias = mktime($LocalHour24, $LocalMinute, $LocalSecond, $LocalMonth, $LocalMonthDay + 1, $LocalYear) - $UTValue - 86400; //(-) = DST/ST commence, (+) = DST/ST terminate
}
if ($Bias > 0) { //DST/ST termination detected
if (date('Z', $UTValue) !== date('Z', $UTValue + $Bias)) { //Local time occurred in relapse range; System assumed 1st iteration
$ReturnData['relapse'] = $UTValue + $Bias;
}
if (date('Z', $UTValue - $Bias) !== date('Z', $UTValue)) { //Local time occurred in relapse range; System assumed 2nd iteration
$ReturnData['initial'] = $UTValue - $Bias;
}
//Else local time is outside of relapse range
} //Else no DST/ST transition, or transition is commencement
return $ReturnData;
}
/*--></?php */?>
Do not be confused by the start and end tags; The interleaved PHP-comment and HTML-comment delimiters prevent PHP code containing ">" from appearing as literal text when viewing or editing an HTML file with embedded PHP code.
Convert timestamp to time();
<?php
function wp_mktime($_timestamp = ''){
if($_timestamp){
$_split_datehour = explode(' ',$_timestamp);
$_split_data = explode("-", $_split_datehour[0]);
$_split_hour = explode(":", $_split_datehour[1]);
return mktime ($_split_hour[0], $_split_hour[1], $_split_hour[2], $_split_data[1], $_split_data[2], $_split_data[0]);
}
}
?>
[NOTE BY danbrown AT php DOT net: See also (http://php.net/strtotime)]
With combination of mktime and getDate and date() you can add hours / seconds / days / months / years to ANY timestamp. Use strtotime() function to convert any type of dates to timestamp
<?php
public function addMonthToDate($timeStamp, $totalMonths=1){
// You can add as many months as you want. mktime will accumulate to the next year.
$thePHPDate = getdate($timeStamp); // Covert to Array
$thePHPDate['mon'] = $thePHPDate['mon']+$totalMonths; // Add to Month
$timeStamp = mktime($thePHPDate['hours'], $thePHPDate['minutes'], $thePHPDate['seconds'], $thePHPDate['mon'], $thePHPDate['mday'], $thePHPDate['year']); // Convert back to timestamp
return $timeStamp;
}
public function addDayToDate($timeStamp, $totalDays=1){
// You can add as many days as you want. mktime will accumulate to the next month / year.
$thePHPDate = getdate($timeStamp);
$thePHPDate['mday'] = $thePHPDate['mday']+$totalDays;
$timeStamp = mktime($thePHPDate['hours'], $thePHPDate['minutes'], $thePHPDate['seconds'], $thePHPDate['mon'], $thePHPDate['mday'], $thePHPDate['year']);
return $timeStamp;
}
public function addYearToDate($timeStamp, $totalYears=1){
$thePHPDate = getdate($timeStamp);
$thePHPDate['year'] = $thePHPDate['year']+$totalYears;
$timeStamp = mktime($thePHPDate['hours'], $thePHPDate['minutes'], $thePHPDate['seconds'], $thePHPDate['mon'], $thePHPDate['mday'], $thePHPDate['year']);
return $timeStamp;
}
?>
NB: one 'gotcha' with the implementation of mktime()'s parameters:
<?php
for( $i = 1 ; $i <= 12 ; $i++ )
{
echo "Month '$i' is: " . date( "F" , mktime( 0 , 0 , 0 , $i ) ) . "\n";
}
?>
Will output:
Month '1' is: January
Month '2' is: March
Month '3' is: March
Month '4' is: May
Month '5' is: May
Month '6' is: July
Month '7' is: July
Month '8' is: August
Month '9' is: October
Month '10' is: October
Month '11' is: December
Month '12' is: December
on the 31st day of every month.
Why? Because the 5th parameter "day" defaults to "right now," which will not work reliably for days after the 28th.
To make sure this doesn't happen, specify the first day of the month:
<?php
mktime( 0 , 0 , 0 , $i , 1 )
?>
It may be useful to note that no E_WARNINGS or E_NOTICES are give if you specify a date <1901 or >2038 on systems where time_t is a 32bit signed integer.
If a date is specified outside of the allowed range you may get some unexpected results as no timestamp will be returned.
There are several notes for mktime which use the number 86400 to differentiate two days. However this technique may pose a problem in case there is a day where the hour change between the two dates to compare.
Consequently, if you want the timestamp difference between the day where the hour change and the next day, it will not be equals to 86400 but either 82800 in case its the winter change of hour day or 90000 for the summer change of hour day.
For example in 2006 :
<?php
echo mktime(0,0,0,10,29,2006) - mktime(0,0,0,10,30,2006); // -90 000
?>
If the month is greater than 12, it goes into the next year. If it is less than 1, it goes into the previous year. Generally, it behaves as you'd expect it to :-)
Examples:
<?php
// January 1, 2005
print date ("F j, Y", mktime (0,0,0,13,1,2004));
// December 1, 2003
print date ("F j, Y", mktime (0,0,0,0,1,2004));
// February 1, 2005
print date ("F j, Y", mktime (0,0,0,14,1,2004));
// November 1, 2003
print date ("F j, Y", mktime (0,0,0,-1,1,2004));
?>
Consider skipping months with mktime().
$nextmonth = date("M",mktime(0,0,0,date("n")+1,date("j"),date("Y")));
On any day in Januari you expect to get Feb, right?
But on January 30th you'll get Mar. It will try Feb 30th, which doesn't exist, and skips another month. Therefore in this case present a day value that will certainly be legal in any month, like day "1".
This will give you next month on any day of the year:
$nextmonth = date("M",mktime(0,0,0,date("n")+1,1,date("Y")));
I think it is important to note that the timestamp returned is based upon the number of seconds from the epoch GMT, and then modified by the time zone settings on the server.
Thus...
mktime(0,0,0,1,1,1970) will not always return 0. For example with the US eastern time zone (GMT-5) will return 18000 (5 hours past the epoch) and the same function with the time zone set to the US pacific time zone (GMT-8) will return 28800 (8 hours past the epoch).
In an instance where you want time zone independence, you should use the function gmmktime()
With regard to Example 1 and using mktime to correct out-of-range input.
It should be noted that mktime will implement day light saving amends. Consider the following:
<?php
print(date("d/m/Y H:i:s",mktime(0,0,0,3,(27 + 1),2004)));
?>
OUTPUT "28/03/2004 02:00:00"
<?php
print(date("d/m/Y H:i:s",(mktime(0,0,0,3,27,2004) + (((1 * 24) * 60) * 60))));
?>
OUTPUT "28/03/2004 00:00:00"
Dependent on your requirements this may or may be desirable
I do a lot of work using dates and times.
I use mktime() a lot. One wee word of caution over excessive use of incrementing the day parameter. Something I do quite a lot and works great for reasonable ranges.
I recently found, however, that the function gave erroneous results when too many days were added (i.e. around 6 months worth).
Changed to using mktime for the basic date then adding the required seconds to the integer datetime value.
e.g. instead of
<?php
for ($i=0; $i<$no_of_four_week_periods,$i++)
{
$curdatetm = mktime(0,0,0,4,(1+($i*28)),$curyr);
}
?>
.. try something like ..
<?php
$basedatetm = mktime(0,0,0,4,1,$curyr);
for ($i=0; $i<$no_of_four_week_periods,$i++)
{
$cudatetm = $basedatetm + ($i*28*24*60*60);
}
?>
cheers
caculate days between two date
<?php
// end date is 2008 Oct. 11 00:00:00
$_endDate = mktime(0,0,0,11,10,2008);
// begin date is 2007 May 31 13:26:26
$_beginDate = mktime(13,26,26,05,31,2007);
$timestamp_diff= $_endDate-$_beginDate +1 ;
// how many days between those two date
$days_diff = $timestamp_diff/86400;
?>
When calling mktime(), be sure that you use values without leading zeros. The date comes out wrong in the following example:
$endts = mktime(12, 00, 00, 12, 08, 2008, 0);
(note the 08 instead of just 8)
C's scanf() has a format specification where leading 0's can indicate an octal value - perhaps this is related?
Here is what I use to calculate age. It took me 30 minutes to write and it's quite accurate. What it has special is that it's calculating the number of days a year has (float number), by testing if a year is a leap one or not. This number is used to compute the age.
<?php
function get_age($date_start, $date_end) {
$t_lived = get_timestamp($date_end) - get_timestamp($date_start);
$seconds_one_year = get_days_per_year($date_start, $date_end) * 24 * 60 * 60;
$age = array();
$age['years_exact'] = $t_lived / $seconds_one_year;
$age['years'] = floor($t_lived / $seconds_one_year);
$seconds_remaining = $t_lived % $seconds_one_year;
$age['days'] = round($seconds_remaining / (24 * 60 * 60));
return $age;
}
function get_timestamp($date) {
list($y, $m, $d) = explode('-', $date);
return mktime(0, 0, 0, $m, $d, $y);
}
function get_days_per_year($date_start, $date_end) {
list($y1) = explode('-', $date_start);
list($y2) = explode('-', $date_end);
$years_days = array();
for($y = $y1; $y <= $y2; $y++) {
$years_days[] = date('L', mktime(0, 0, 0, 1, 1, $y)) ? 366 : 365;
}
return round(array_sum($years_days) / count($years_days), 2);
}
$date_birth = '1979-10-12';
$date_now = date('Y-m-d');
$age = get_age($date_birth, $date_now);
echo '<pre>';
print_r($age);
echo '</pre>';
?>
It will display something like this:
Array
(
[years_exact] => 28.972974329491
[years] => 28
[days] => 355
)
How to get the first and last dates of the last quarter - useful for things like tax return dates etc. by Justin
<?php
function getLastQuarter() {
// Returns an array with a start and end date for the last quarter from todays date
// eg. If today is 23 Feb 2009, returns $x['start'] = 1 Oct 2008, $x[end] = 31 Dec 2008
$year = date("Y",mktime());
$month = date("m",mktime());
// Formula to get a quarter in the year from a month
$startmth = $month - 3 - (($month-1) % 3 );
// Fix up Jan - Feb to get LAST year's quarter dates (Oct - Dec)
if ($startmth == -2) {
$startmth+=12;
$year-=1;
}
$endmth = $startmth+2;
$last_quarter['start'] = mktime(0,0,0,$startmth,1,$year);
$last_quarter['end'] = mktime(0,0,0,$endmth,date("t",mktime(0,0,0,$endmth,1,$year)),$year);
return $last_quarter;
}
// Example - print first and last dates of last quarter.
echo "First day of last quarter was : " . date("d-M-Y",$lastquarter['start']) . "\n";
echo "Last day of last quarter was : " . date("d-M-Y",$lastquarter['end']) . "\n";
// For 2 August 2009, returns:
// First day of last quarter was : 01-Apr-2009
// Last day of last quarter was : 30-Jun-2009
//
?>
