Things to be aware of when using week numbers with years.
<?php
echo date("YW", strtotime("2011-01-07")); // gives 201101
echo date("YW", strtotime("2011-12-31")); // gives 201152
echo date("YW", strtotime("2011-01-01")); // gives 201152 too
?>
BUT
<?php
echo date("oW", strtotime("2011-01-07")); // gives 201101
echo date("oW", strtotime("2011-12-31")); // gives 201152
echo date("oW", strtotime("2011-01-01")); // gives 201052 (Year is different than previous example)
?>
Reason:
Y is year from the date
o is ISO-8601 year number
W is ISO-8601 week number of year
Conclusion:
if using 'W' for the week number use 'o' for the year.
date
(PHP 4, PHP 5)
date — Formatta una data o orario locale
Descrizione
string date
( string
$format
[, int $timestamp = time()
] )
Restituisce una stringa formattata in accordo con il formato della stringa data usando
l'intero timestamp dato o l'orario corrente
se nessun timestamp è dato. In altre parole, timestamp
è opzionale e di default prende il valore di time().
Elenco dei parametri
-
format -
Il formato della data da produrre come string. Vedere le opzioni di formattazione sottostanti. Ci sono anche tante costanti delle date predefinite che possono essere usate al loro posto, così per esempio
DATE_RSScontiene la stringa dal formato 'D, d M Y H:i:s'.I seguenti caratteri sono riconosciuti nel parametro stringa formatCarattere del formatDescrizione Esempio di valori restituiti Giorno --- --- d Giorno del mese, 2 cifre con zero iniziali 01 a 31 D Una rappresentazione testuale di un giorno, tre lettere Mon a Sun j Giorno del mese senza gli zero iniziali 1 a 31 l ('L' minuscola) Una rappresentazione testuale completa del giorno della settimana Sunday a Saturday N Rappresentazione numerica ISO-8601 del giorno della settimana (aggiunto in PHP 5.1.0) 1 (per Lunedì) a 7 (per Domenica) S Suffisso ordinale inglese per il giorno del mese, 2 caratteri st, nd, rd o th. Funziona bene con j w Rappresentazione numerica del giorno della settimana 0 (per Domenica) a 6 (per Sabato) z Il giorno dell'anno (partendo da 0) 0 a 365 Settimana --- --- W Numero della settimana dell'anno ISO-8601, le settimane iniziano di Lunedì (aggiunto in PHP 4.1.0) Esempio: 42 (la 42esima settimana nell'anno) Mese --- --- F Una rappresentazione testuale completa di un mese, come January o March January a December m Rappresentazione numerica di un mese, con gli zero iniziali 01 a 12 M Una piccola rappresentazione testuale di un mese, tre lettere Jan a Dec n Rappresentazione numerica di un mese, senza gli zero iniziali 1 a 12 t Numero di giorni nel dato mese 28 a 31 Anno --- --- L Se si tratta di un anno bisestile 1 se è un anno bisestile, 0 in caso contrario. o Il numero dell'anno ISO-8601. Questo ha lo stesso valore di Y, eccetto che se il numero della settimana ISO (W) appartiene all'anno precedente o successivo, viene invece utilizzato quell'anno. (aggiunto in PHP 5.1.0) Esempi: 1999 o 2003 Y Una rappresentazione numerica completa di un anno, 4 cifre Esempi: 1999 o 2003 y Una rappresentazione a due cifre di un anno Esempi: 99 o 03 Orario --- --- a Ante meridiem e Post meridiem in minuscole am o pm A Ante meridiem e Post meridiem in maiuscole AM o PM B Orario di Internet Swatch 000 a 999 g Formato a 12 ore di un'ora senza gli zero iniziali 1 a 12 G Formato a 24 ore di un'ora senza gli zero iniziali 0 a 23 h Formato a 12 ore di un'ora con gli zero iniziali 01 a 12 H Formato a 24 ore di un'ora con gli zero iniziali 00 a 23 i Minuti con gli zero iniziali 00 a 59 s Secondi, con gli zero iniziali 00 a 59 u Microsecondi (aggiunto in PHP 5.2.2). Notare che date() genererà sempre 000000 dato che prende un parametro integer, mentre DateTime::format() supporta i microsecondi. Esempio: 654321 Fuso orario --- --- e Identificatore del fuso orario (aggiunto in PHP 5.1.0) Esempi: UTC, GMT, Atlantic/Azores I (i maiuscola) Se la data è o no in ora legale 1 se è ora legale, 0 in caso contrario. O Differenza dall'ora di Greenwich (GMT) in ore Esempio: +0200 P Differenza dall'ora di Greenwich (GMT) con due punti tra ore e minuti (aggiunto in PHP 5.1.3) Esempio: +02:00 T Abbreviazione del fuso orario Esempio: EST, MDT ... Z Differenza del fuso orario in secondi. La differenza per i fusi orari ad ovest di UTC è sempre negativa, e per quelli all'est di UTC è sempre positiva. -43200 a 50400 Data/Ora Completa --- --- c Data ISO 8601 (aggiunta in PHP 5) 2004-02-12T15:19:21+00:00 r Data formattata in » RFC 2822 Esempio: Thu, 21 Dec 2000 16:01:07 +0200 U Il numero di secondi dalla Unix Epoch (Gennaio 1 1970 00:00:00 GMT) Vedere anche time() I caratteri non riconosciuti nella stringa formato saranno stampati così come sono. Il formato Z restituirà sempre 0 quando si utilizza gmdate().
Nota:
Poichè questa funzione accetta solo timestamp integer il carattere di formato u è utile solo quando si utilizza la funzione date_format() con i timestamp basati sull'utente creati con date_create().
-
timestamp -
Il parametro opzionale
timestampè un integer timestamp Unix che ha come default l'ora locale attuale se untimestampnon è fornito. In altre parole, ha come default il valore di time().
Valori restituiti
Restituisce una stringa data formattata. Se viene utilizzato un valore non numerico per
timestamp, viene restituito FALSE e viene
emesso un errore di livello E_WARNING.
Errori/Eccezioni
Ogni chiamata a una funzione data/ora genera un E_NOTICE
se il time zone non è valido, e/o un messaggio E_STRICT
o E_WARNING
se si usano le impostazioni di sistema o la variabile d'ambiente TZ.
Vedere anche date_default_timezone_set()
Log delle modifiche
| Versione | Descrizione |
|---|---|
| 5.1.0 | L'intervallo valido di un timestamp è tipicamente da Ven, 13 Dec 1901 20:45:54 GMT a Mar, 19 Gen 2038 03:14:07 GMT. (Queste sono le date che corrispondono al valore minimo e massimo per un intero con segno a 32-bit). Tuttavia, prima di PHP 5.1.0 questo intervallo era limitato da 01-01-1970 a 19-01-2038 su alcuni sistemi (es. Windows). |
| 5.1.0 |
Ora emette gli errori time zone |
| 5.1.1 |
Ci sono delle costanti utili
dei formati di data/ora standard che possono essere usate per specificare il
parametro format.
|
Esempi
Example #1 Esempi di date()
<?php
// imposta il fuso orario di default da utilizzare. Disponibile da PHP 5.1
date_default_timezone_set('UTC');
// Stampa qualcosa di simile a: Monday
echo date("l");
// Stampa qualcosa di simile a: Monday 8th of August 2005 03:12:46 PM
echo date('l jS \of F Y h:i:s A');
// Stampa: July 1, 2000 is on a Saturday
echo "July 1, 2000 is on a " . date("l", mktime(0, 0, 0, 7, 1, 2000));
/* usa le costanti nel parametro format */
// stampa qualcosa di simile a: Wed, 25 Sep 2013 15:28:57 -0700
echo date(DATE_RFC2822);
// stampa qualcosa di simile a: 2000-07-01T00:00:00+00:00
echo date(DATE_ATOM, mktime(0, 0, 0, 7, 1, 2000));
?>
È possibile evitare che un carattere riconosciuto nella stringa formato venga espanso effettuando l'escape di esso anteponendo un backslash. Se il carattere con un backslash è già una sequenza speciale, potrebbe essere necessario effettuare l'escape anche del backslash.
Example #2 Effettuare l'escape dei caratteri in date()
<?php
// stampa qualcosa di simile a: Wednesday the 15th
echo date('l \t\h\e jS');
?>
È possibile utilizzare insieme date() e mktime() per trovare date nel futuro o nel passato.
Example #3 Esempio di date() e di mktime()
<?php
$tomorrow = mktime(0, 0, 0, date("m") , date("d")+1, date("Y"));
$lastmonth = mktime(0, 0, 0, date("m")-1, date("d"), date("Y"));
$nextyear = mktime(0, 0, 0, date("m"), date("d"), date("Y")+1);
?>
Nota:
Questo può essere più affidabile rispetto che semplicemente aggiungere o sottrarre il numero di secondi in un giorno o in un mese ad un timestamp a causa dell'ora legale.
Alcuni esempi della formattazione date(). Notare che si dovrebbe effettuare l'escape di qualsiasi altro carattere, come tutti quelli che attualmente hanno un significato speciale produrranno risultati indesiderati, e ad altri caratteri potrebbe essere assegnato un significato nelle versioni future di PHP. Quando si effettua l'escape, assicurarsi di usare gli apici singoli in modo da evitare che i caratteri come \n divengano nuove linee.
Example #4 Formattazione di date()
<?php
// Assumendo che oggi sia Il 10 Marzo, 2001, 5:16:18 pm, e che noi siamo nel
// Fuso Orario Mountain Standard Time (MST)
$today = date("F j, Y, g:i a"); // March 10, 2001, 5:16 pm
$today = date("m.d.y"); // 03.10.01
$today = date("j, n, Y"); // 10, 3, 2001
$today = date("Ymd"); // 20010310
$today = date('h-i-s, j-m-y, it is w Day'); // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$today = date('\i\t \i\s \t\h\e jS \d\a\y.'); // it is the 10th day.
$today = date("D M j G:i:s T Y"); // Sat Mar 10 17:16:18 MST 2001
$today = date('H:m:s \m \i\s\ \m\o\n\t\h'); // 17:03:18 m is month
$today = date("H:i:s"); // 17:16:18
$today = date("Y-m-d H:i:s"); // 2001-03-10 17:16:18 (the MySQL DATETIME format)
?>
Per formattare le date in altri lingue, si dovrebbero utilizzare le funzioni setlocale() e strftime() al posto di date().
Note
Nota:
Per generare un timestamp da una stringa che rappresenta la data, si può essere in grado di utilizzare strtotime(). Inoltre, alcuni database hanno delle funzioni per convertire i loro formati data in timestamp (come la funzione » UNIX_TIMESTAMP di MySQL).
Suggerimento
Il timestamp dell'inizio della richiesta è disponibile in $_SERVER['REQUEST_TIME'] da PHP 5.1.
Vedere anche:
- gmdate() - Formatta una data/ora GMT/UTC
- idate() - Format a local time/date as integer
- getdate() - Riceve informazioni su data/orario
- getlastmod() - Restituisce la data dell'ultima modifica alla pagina
- mktime() - Restituisce la UNIX timestamp per una data
- strftime() - Formatta una data/orario locale accordandola/o alle impostazioni locali according to locale settings
- time() - Restituisce l'attuale UNIX timestamp
- strtotime() - Analizza le descrizioni testuali di datetime in Inglese nell'UNIX timestamp
- Costanti di DateTime Predefinite
add a note
User Contributed Notes 42 notes
Jimmy ¶
3 years ago
adityabhai at gmail dot com ¶
1 year ago
For Microseconds, we can get by following:
echo date('Ymd His'.substr((string)microtime(), 1, 8).' e');
Thought, it might be useful to someone !
FiraSEO ¶
2 years ago
this how you make an HTML5 <time> tag correctly
<?php
echo '<time datetime="'.date('c').'">'.date('Y - m - d').'</time>';
?>
in the "datetime" attribute you should put a machine-readable value which represent time , the best value is a full time/date with ISO 8601 ( date('c') ) ,,, the attr will be hidden from users
and it doesn't really matter what you put as a shown value to the user,, any date/time format is okay !
This is very good for SEO especially search engines like Google .
bakerj417 at gmail dot com ¶
2 years ago
If you are having an issue getting u to work so is everyone else. The solution that I am using which I found on another site(so not taking credit) is to use this:
date("Y/m/d H:i:s"). substr((string)microtime(), 1, 6);
that will give you:
yyyy/mm/dd hh:ii:ss.uuuuuu
hope this helps someone in need!
thanks all
Anonymous ¶
11 months ago
It's common for us to overthink the complexity of date/time calculations and underthink the power and flexibility of PHP's built-in functions. Consider http://php.net/manual/en/function.date.php#108613
<?php
function get_time_string($seconds)
{
return date('H:i:s', strtotime("2000-01-01 + $seconds SECONDS"));
}
Anonymous ¶
6 years ago
Correct format for a MySQL DATETIME column is
<?php $mysqltime = date ("Y-m-d H:i:s", $phptime); ?>
jock ¶
8 months ago
As of PHP 5.3.3, date('c') will produce a string like this:
2014-06-17T16:22:42+02:00
Instead date (DATE_ISO8601) will produce:
2014-06-17T16:23:36+0200
which lacks the semicolon in the timezone part. Both are ISO8601 compliant anyway, but I found that the latter has better compatibility with other languages like python.
Leopietroni ¶
2 years ago
This function will add working day to a given timestamp
<?php
function addworkinday($timestamp,$daystoadd){
$dayoftheweek = date("N",$timestamp);
$sum =$dayoftheweek +$daystoadd;
while ($sum >= 6) {
$daystoadd=$daystoadd+1;
$sum=$sum-1;
}
return $timestamp +(60*60*24*$daystoadd);
}
?>
webmaster1989 at gmail dot com ¶
2 years ago
Sometimes it is very useful to convert a sql timestamp to an also called NTP time. This is often used as time date notation in XML RSS pages. To convert a timestamp to this NTP notation try the following:
<?php
echo date('D, d M Y h:i:s O', strtotime ($timestamp);
?>
nathan ¶
2 years ago
<?php
/* the following variables are set to appropriate
characters recognized by php version 5 that
will get the date. To display the date, we have
to use 'echo' or 'print' to send the variable
data to the browser
*/
$day=date("l");
$date=date("j");
$suffix=date("S");
$month=date("F");
$year=date("Y");
echo $day . ", " . $month . " " . $date . $suffix . ", " . $year;
?>
rudimentary, simple way to due things, but it gets the job done for someone learning more on the subject.
Tim Connolly ¶
2 years ago
Here's my solution for looking up the month number by name (used when parsing an 'ls'):
<?php
for($m=1;$m<=12;$m++){
$month=date("M",mktime(0,0,0,$m,1,2000));
$mon["$month"]=$m;
}
?>
eduardo at digmotor dot com dot br ¶
5 years ago
Thanks to tcasparr at gmail dot com for the great idea (at least for me) ;)
I changed the code a little to replicate the functionality of date_parse_from_format, once I don't have PHP 5.3.0 yet. This might be useful for someone. Hope you don't mind changing your code tcasparr at gmail dot com.
<?php
/*******************************************************
* Simple function to take in a date format and return array of associated
* formats for each date element
*
* @return array
* @param string $strFormat
*
* Example: Y/m/d g:i:s becomes
* Array
* (
* [year] => Y
* [month] => m
* [day] => d
* [hour] => g
* [minute] => i
* [second] => s
* )
*
* This function is needed for PHP < 5.3.0
********************************************************/
function dateParseFromFormat($stFormat, $stData)
{
$aDataRet = array();
$aPieces = split('[:/.\ \-]', $stFormat);
$aDatePart = split('[:/.\ \-]', $stData);
foreach($aPieces as $key=>$chPiece)
{
switch ($chPiece)
{
case 'd':
case 'j':
$aDataRet['day'] = $aDatePart[$key];
break;
case 'F':
case 'M':
case 'm':
case 'n':
$aDataRet['month'] = $aDatePart[$key];
break;
case 'o':
case 'Y':
case 'y':
$aDataRet['year'] = $aDatePart[$key];
break;
case 'g':
case 'G':
case 'h':
case 'H':
$aDataRet['hour'] = $aDatePart[$key];
break;
case 'i':
$aDataRet['minute'] = $aDatePart[$key];
break;
case 's':
$aDataRet['second'] = $aDatePart[$key];
break;
}
}
return $aDataRet;
}
?>
Also, if you need to change the format of dates:
<?php
function changeDateFormat($stDate,$stFormatFrom,$stFormatTo)
{
// When PHP 5.3.0 becomes available to me
//$date = date_parse_from_format($stFormatFrom,$stDate);
//For now I use the function above
$date = dateParseFromFormat($stFormatFrom,$stDate);
return date($stFormatTo,mktime($date['hour'],
$date['minute'],
$date['second'],
$date['month'],
$date['day'],
$date['year']));
}
?>
Anonymous ¶
1 year ago
To quickly convert date("N") to a 0 based index with Sunday being represented as 0, you can run it against modulus 7:
<?php
$first_of_month_index = date('N', strtotime('4/1/1990')) % 7;
?>
Bas Vijfwinkel ¶
2 years ago
Note that some formatting options are different from MySQL.
For example using a 24 hour notation without leading zeros is the option '%G' in PHP but '%k' in MySQL.
When using dynamically generated date formatting string, be careful to generate the correct options for either PHP or MySQL.
Edward Rudd ¶
5 years ago
To actually make use ot the "u" (microsecond) you need to use the DateTime object and not the date() function.
For example
<?php
$t = microtime(true);
$micro = sprintf("%06d",($t - floor($t)) * 1000000);
$d = new DateTime( date('Y-m-d H:i:s.'.$micro,$t) );
print $d->format("Y-m-d H:i:s.u");
?>
mel dot boyce at gmail dot com ¶
8 years ago
I've been flicking through the comments looking for some succinct date code and have noticed an alarming number of questions and over-burdened examples related to date mathematics. One of the most useful skills you can utilize when performing date math is taking full advantage of the UNIX timestamp. The UNIX timestamp was built for this kind of work.
An example of this relates to a comment made by james at bandit-dot-co-dot-en-zed. James was looking for a way to calculate the number of days which have passed since a certain date. Rather than using mktime() and a loop, James can subtract the current timestamp from the timestamp of the date in question and divide that by the number of seconds in a day:
<?php
$days = floor((time() - strtotime("01-Jan-2006"))/86400);
print("$days days have passed.\n");
?>
Another usage could find itself in a class submitted by Kyle M Hall which aids in the creation of timestamps from the recent past for use with MySQL. Rather than the looping and fine tuning of a date, Kyle can use the raw UNIX timestamps (this is untested code):
<?php
$ago = 14; // days
$timestamp = time() - ($ago * 86400);
?>
Hopefully these two examples of "UNIX-style" timestamp usage will help those finding date mathematics more elusive than it should be.
SpikeDaCruz ¶
8 years ago
The following function will return the date (on the Gregorian calendar) for Orthodox Easter (Pascha). Note that incorrect results will be returned for years less than 1601 or greater than 2399. This is because the Julian calendar (from which the Easter date is calculated) deviates from the Gregorian by one day for each century-year that is NOT a leap-year, i.e. the century is divisible by 4 but not by 10. (In the old Julian reckoning, EVERY 4th year was a leap-year.)
This algorithm was first proposed by the mathematician/physicist Gauss. Its complexity derives from the fact that the calculation is based on a combination of solar and lunar calendars.
<?php
function getOrthodoxEaster($date){
/*
Takes any Gregorian date and returns the Gregorian
date of Orthodox Easter for that year.
*/
$year = date("Y", $date);
$r1 = $year % 19;
$r2 = $year % 4;
$r3 = $year % 7;
$ra = 19 * $r1 + 16;
$r4 = $ra % 30;
$rb = 2 * $r2 + 4 * $r3 + 6 * $r4;
$r5 = $rb % 7;
$rc = $r4 + $r5;
//Orthodox Easter for this year will fall $rc days after April 3
return strtotime("3 April $year + $rc days");
}
?>
ghotinet ¶
4 years ago
Most spreadsheet programs have a rather nice little built-in function called NETWORKDAYS to calculate the number of business days (i.e. Monday-Friday, excluding holidays) between any two given dates. I couldn't find a simple way to do that in PHP, so I threw this together. It replicates the functionality of OpenOffice's NETWORKDAYS function - you give it a start date, an end date, and an array of any holidays you want skipped, and it'll tell you the number of business days (inclusive of the start and end days!) between them.
I've tested it pretty strenuously but date arithmetic is complicated and there's always the possibility I missed something, so please feel free to check my math.
The function could certainly be made much more powerful, to allow you to set different days to be ignored (e.g. "skip all Fridays and Saturdays but include Sundays") or to set up dates that should always be skipped (e.g. "skip July 4th in any year, skip the first Monday in September in any year"). But that's a project for another time.
<?php
function networkdays($s, $e, $holidays = array()) {
// If the start and end dates are given in the wrong order, flip them.
if ($s > $e)
return networkdays($e, $s, $holidays);
// Find the ISO-8601 day of the week for the two dates.
$sd = date("N", $s);
$ed = date("N", $e);
// Find the number of weeks between the dates.
$w = floor(($e - $s)/(86400*7)); # Divide the difference in the two times by seven days to get the number of weeks.
if ($ed >= $sd) { $w--; } # If the end date falls on the same day of the week or a later day of the week than the start date, subtract a week.
// Calculate net working days.
$nwd = max(6 - $sd, 0); # If the start day is Saturday or Sunday, add zero, otherewise add six minus the weekday number.
$nwd += min($ed, 5); # If the end day is Saturday or Sunday, add five, otherwise add the weekday number.
$nwd += $w * 5; # Add five days for each week in between.
// Iterate through the array of holidays. For each holiday between the start and end dates that isn't a Saturday or a Sunday, remove one day.
foreach ($holidays as $h) {
$h = strtotime($h);
if ($h > $s && $h < $e && date("N", $h) < 6)
$nwd--;
}
return $nwd;
}
$start = strtotime("1 January 2010");
$end = strtotime("13 December 2010");
// Add as many holidays as desired.
$holidays = array();
$holidays[] = "4 July 2010"; // Falls on a Sunday; doesn't affect count
$holidays[] = "6 September 2010"; // Falls on a Monday; reduces count by one
echo networkdays($start, $end, $holidays); // Returns 246
?>
Or, if you just want to know how many work days there are in any given year, here's a quick function for that one:
<?php
function workdaysinyear($y) {
$j1 = mktime(0,0,0,1,1,$y);
if (date("L", $j1)) {
if (date("N", $j1) == 6)
return 260;
elseif (date("N", $j1) == 5 or date("N", $j1) == 7)
return 261;
else
return 262;
}
else {
if (date("N", $j1) == 6 or date("N", $j1) == 7)
return 260;
else
return 261;
}
}
?>
JonathanCross.com ¶
6 years ago
<?php
// A demonstration of the new DateTime class for those
// trying to use dates before 1970 or after 2038.
?>
<h2>PHP 2038 date bug demo (php version <?php echo phpversion(); ?>)</h1>
<div style='float:left;margin-right:3em;'>
<h3>OLD Buggy date()</h3>
<?php
$format='F j, Y';
for ( $i = 1900; $i < 2050; $i++) {
$datep = "$i-01-01";
?>
Trying: <?php echo $datep; ?> = <?php echo date($format, strtotime($datep)); ?><br>
<?php
}
?></div>
<div style='float:left;'>
<h3>NEW DateTime Class (v 5.2+)</h3><?php
for ( $i = 1900; $i < 2050; $i++) {
$datep = "$i-01-01";
$date = new DateTime($datep);
?>
Trying: <?php echo $datep; ?> = <?php echo $date->format($format); ?><br>
<?php
}
?></div>
gerben at gerbenwijnja dot nl ¶
3 years ago
I use the function below to calculate the Unix timestamp of the start of a week. It includes a boolean flag to request a GMT offset instead of the current locale setting.
<?php
function getWeekOffsetTimestamp($year, $week, $useGmt = false) {
if ($useGmt) {
// Backup timezone and set to GMT
$timezoneSettingBackup = date_default_timezone_get();
date_default_timezone_set("GMT");
}
// According to ISO-8601, January 4th is always in week 1
$halfwayTheWeek = strtotime($year."0104 +".($week - 1)." weeks");
// Subtract days to Monday
$dayOfTheWeek = date("N", $halfwayTheWeek);
$daysToSubtract = $dayOfTheWeek - 1;
// Calculate the week's timestamp
$unixTimestamp = strtotime("-$daysToSubtract day", $halfwayTheWeek);
if ($useGmt) {
// Reset timezone to backup
date_default_timezone_set($timezoneSettingBackup);
}
return $unixTimestamp;
}
?>
lb at bostontech dot net ¶
5 years ago
Not sure why this got ignored the first time, but this is an even simpler way to check leap year:
<?php
function isLeapYear($year)
{ return ((($year%4==0) && ($year%100)) || $year%400==0) ? (true):(false); }
?>
jc ¶
7 years ago
date("W") returns the iso8601 week number, while date("Y") returns the _current_ year. This can lead to odd results. For example today (dec 31, 2007) it returns 1 for the week and of course 2007 for the year. This is not wrong in a strict sense because iso defines this week as the first of 2008 while we still have 2007.
So, if you don't have another way to safely retrieve the year according to the iso8061 week-date - strftime("%G") doesn't work on some systems -, you should be careful when working with date("W").
For most cases strftime("%W") should be a safe replacement.
[edit: Much easier is to use "o" (lower case O) instead of "Y"]
Just.Kevin ¶
5 years ago
In order to determine if a year is a leap year an earlier poster suggested simply checking to see if the year is a multiple of four:
<?php
function is_leapyear_broken($year = 2004) {
return ($year%4)==0;
}
?>
While this will work for the majority of years it will not work on years that are multiples of 100 but not multiples of 400 i.e.(2100).
A function not using php's date() function that will also account for this small anomaly in leap years:
<?php
function is_leapyear_working($year = 2004) {
if((($year%4==0) && ($year%100!=0)) || $year%400==0) {
return true;
}
return false;
}
?>
While is_leapyear_working will not return true for the few non-leap years divisible by four I couldn't tell you if this is more or less efficient than using php's date() as an even earlier poster suggested:
<?php
function is_leapyear($year = 2004) {
$is_leap = date('L', strtotime("$year-1-1"));
return $is_leap;
}
?>
Anon ¶
2 years ago
I needed to convet a duration timestamp into H:i:s but whenever I did it kept bringing 5 back as 01:00:05 (due to some DST stuff) so I made this function to replace date(). It has no optimisations but hopefully someone might find it useful:
<?php
function get_time_string(){
$time = 3600+(60*32)+(50); // 01:32:50
$time_string = '';
$hours = (int)($time/(60*60));
if(strlen($hours) > 1){
$time_string = $hours.':';
}else{
$time_string = '0'.$hours.':';
}
$minutes = (int)(($time%(60*60))/(60));
if($minutes >= 1){
if(strlen($minutes) > 1){
$time_string .= $minutes.':';
}else{
$time_string .= '0'.$minutes.':';
}
$seconds = ($time%(60*60))%(60);
if(strlen($seconds) > 1){
$time_string .= $seconds;
}else{
$time_string .= '0'.$seconds;
}
}else{
if(strlen($time) > 1){
$time_string .= '00:'.$time;
}else{
$time_string .= '00:0'.$time;
}
}
return $time_string;
}
?>
matthew dot hotchen at worldfirst dot com ¶
1 year ago
FYI: there's a list of constants with predefined formats on the DateTime object, for example instead of outputting ISO 8601 dates with:
<?php
echo date('c');
?>
or
<?php
echo date('Y-m-d\TH:i:sO');
?>
You can use
<?php
echo date(DateTime::ISO8601);
?>
instead, which is much easier to read.
david dot leon at gmx dot com ¶
9 months ago
<?php
//date returns microseconds.
function mdate($format, $microtime = null) {
$microtime = explode(' ', ($microtime ? $microtime : microtime()));
if (count($microtime) != 2) return false;
$microtime[0] = $microtime[0] * 1000000;
$format = str_replace('u', $microtime[0], $format);
return date($format, $microtime[1]);
}
?>
echo mdate('Y-m-d H:i:s.u');
2014-05-19 12:41:59.202303
@PeteWilliams ¶
4 years ago
If you want to use HTML5's <date> tag, the following code will generate the machine-readable value for the 'datetime' attribute:
<?php
/**
* formats the date passed into format required by 'datetime' attribute of <date> tag
* if no intDate supplied, uses current date.
* @param intDate integer optional
* @return string
**/
function getDateTimeValue( $intDate = null ) {
$strFormat = 'Y-m-d\TH:i:s.uP';
$strDate = $intDate ? date( $strFormat, $intDate ) : date( $strFormat ) ;
return $strDate;
}
echo getDateTimeValue();
?>
frank at interactinet dot com ¶
3 years ago
If you want to compare this week with the same week last year, here is some code to get you the time at the beginning of the week. You can then add days, hours, etc to get to the day of the week that you want to know about.
<?php
$time_passed = (date('N')-1)* 24 * 3600; // time since start of week in days
$startOfWeek = mktime(0,0,0,date('m'),date('d'),date('Y')) - $time_passed;
$lastyear = $startOfWeek - 365*24*3600;
// make sure time used from last year is the same week of the year
$weekdiff = date('W') - date('W',$lastyear);
if($weekdiff != 0)
{
$lastyear = $lastyear + ($weekdiff*7*24*3600);
}
$lastyear_time_passed = (date('N',$lastyear)-1) * 24 * 3600; // time since start of week in days
$startOfWeek_lastyear = mktime(0,0,0,date('m',$lastyear),date('d',$lastyear),date('Y',$lastyear)) - $lastyear_time_passed;
?>
So now you have the unix time for the start of this week ($startOfWeek), and the start of the same week last year ($startOfWeek_lastyear).
You can convert back to datetime format easily:
<?php
echo date('Y-m-d H:i:s',$startOfWeek).'<br>';
echo date('Y-m-d H:i:s',$startOfWeek_lastyear).'<br><br>';
echo date('l F jS, Y',$startOfWeek).'<br>';
echo date('l F jS, Y',$startOfWeek_lastyear);
?>
Anonymous ¶
1 year ago
Was trying to compare dates when I noticed that:
<?php
var_dump(date('d.m.Y', null));//string(10) "01.01.1970"
var_dump(date('d.m.Y', ''));//bool(false)
?>
Thought it's worth mentioning. Caused some weird logs to be produced in our system since this does not evaluate to the same.
Chris ¶
2 years ago
Use this to convert the local/UTC hour to the UTC/local hour:
<?php
for($utc_to_local = array(), $offset = date('Z'), $h = 0; $h < 24; $utc_to_local[] = date('G', mktime($h++)+$offset));
$local_to_utc = array_flip($utc_to_local);
echo "2 am local is ", $local_to_utc[2], " UTC";
echo "3 pm UTC is ", $utc_to_local[15], " local";
?>
This is useful when you need to do many conversions. Lookup tables are faster than calling date() and mktime() multiple times.
stokestack at gmail dot com ¶
2 years ago
If you want to find your server's timezone offset from GMT, it seems as though you could just do:
date('Z')
to get the number of seconds offset. But PHP requires that you call date_default_timezone_set(). So if you have to hard-code a timezone, why not simply hard-code a variable that tells you the offset from GMT? If you set the timezone to GMT, the dates in your database will still be in local time, but time('Z') will return zero.
To keep your code portable across servers in different timezones, you can do this:
date_default_timezone_set(date_default_timezone_get())
This keeps PHP from complaining that you haven't called date_default_timezone_set(), but makes your code portable. Ridiculous.
m_ocx at yahoo dot com ¶
2 years ago
Here is a cool Date class to implement the date function:
<?php
/*
* @author Gchats
*
* Date class
*/
class Date
{
private $shortDateFormat = "F j, Y";
private $longDateFormat = "F j, Y, g:i a";
private $timestamp = 0;
/**
* Default constructor
*
* @param integer $timestamp unix time stamp
*/
function __construct($timestamp = 0)
{
$this->timestamp = $timestamp;
}
/**
* Returns the given timestamp in the constructor
*
* @return integer time stamp
*/
public function getTime()
{
return (int) $this->timestamp;
}
/*
* Returns long formatted date of the given timestamp
*
* @access public
* @return string Long formatted date
*/
public function long()
{
if ( $this->timestamp > 0 )
{
return date ( $this->longDateFormat , $this->timestamp );
}
else
{
return "";
}
}
/*
* Returns short formatted date of the given timestamp
*
* @access public
* @return string Short formatted date
*/
public function short()
{
if ( $this->timestamp > 0 )
{
return date ( $this->shortDateFormat , $this->timestamp );
}
else
{
return "";
}
}
public function __toString()
{
return $this->timestamp;
}
}
?>
scott at keenot dot es ¶
1 year ago
If anyone needs a really fast function for converting a datetime string (i.e. as retrieved from a MySQL DATETIME entry) into a human-friendly time output analogous to date($format, $time), here's a useful function.
<?php
function fdate($datetimestring = '1970-01-01 00:00:00', $format = 'U') {
// Create a datetime object, return it formatted
// If you want to give credit for this somewhere, thanks.
// You really don't have to though; this is kinda obvious
$dt = new DateTime($datetimestring);
return $dt->format($format);
}
?>
The main purpose of this is to reduce lines of code and allow inline coding. For example:
<?php
/* ... */
echo "This page was submitted on ".fdate($row['created'], 'F j, Y g:i:s A')." and last modified ".fdate($row['modified'], 'F j, Y g:i:s A')."<br />\n";
/* ... */
?>
Anonymous ¶
2 years ago
To find last sunday for given date
<?php
$day = '2012-10-04';
echo 'last sunday : '.date("Y-m-d",strtotime($day." last Sunday "));
?>
output:
last sunday : 2012-09-30
chubby at chicks dot com ¶
6 years ago
<?php
/**
* Checks wether a date is between an interval
*
* Usage:
*
* // check if today is older than 2008/12/31
* var_dump(currentDayIsInInterval('2008/12/31'));
* // check if today is younger than 2008/12/31
* var_dump(currentDayIsInInterval(null,'2008/12/31'));
* // check if today is between 2008/12/01 and 2008/12/31
* var_dump(currentDayIsInInterval('2008/12/01','2008/12/31'));
*
* Will trigger errors if date is in wrong format, notices if $begin > $end
*
* @param string $begin Date string as YYYY/mm/dd
* @param string $end Date string as YYYY/mm/dd
* @return bool
*/
function currentDayIsInInterval($begin = '',$end = '')
{
$preg_exp = '"[0-9][0-9][0-9][0-9]/[0-9][0-9]/[0-9][0-9]"';
$preg_error = 'Wrong parameter passed to function '.__FUNCTION__.' : Invalide date
format. Please use YYYY/mm/dd.';
$interval_error = 'First parameter in '.__FUNCTION__.' should be smaller than
second.';
if(empty($begin))
{
$begin = 0;
}
else
{
if(preg_match($preg_exp,$begin))
{
$begin = (int)str_replace('/','',$begin);
}
else
{
trigger_error($preg_error,E_USER_ERROR);
}
}
if(empty($end))
{
$end = 99999999;
}
else
{
if(preg_match($preg_exp,$end))
{
$end = (int)str_replace('/','',$end);
}
else
{
trigger_error($preg_error,E_USER_ERROR);
}
}
if($end < $begin)
{
trigger_error($interval_error,E_USER_WARNING);
}
$time = time();
$now = (int)(date('Y',$time).date('m',$time).date('j',$time));
if($now > $end or $now < $begin)
{
return false;
}
return true;
}
?>
lehal2 at hotmail dot com ¶
2 years ago
here is an example how you can make numeric days of the week from 1 to 7(Monday to Friday)
<?php
$currentdate = mktime(0, 0, 0, date("m") , date("d"), date("Y"));
echo $day_eg1 = date ('N',$currentdate);
echo $day_eg2 = date("N", $today+1 * 24 * 3600);
echo $day_eg3= date("N", $today+2 * 24 * 3600);
echo $day_eg4 = date("N", $today+3 * 24 * 3600);
echo $day_eg5 = date("N", $today+4 * 24 * 3600);
echo $day_eg6 = date("N", $today+5 * 24 * 3600);
echo $day_eg7 = date("N", $today+6 * 24 * 3600);
?>
blinov vyacheslav AT gmail.com ¶
3 years ago
It was oblivious and discouraging that it dont mentioned in docs. If you will use W to get week number be aware:
first days of year can be in a week of previous year, and week number always has leading zero
<?php
echo date("YW", strtotime("2011-01-07")); // gives 201101
echo date("YW", strtotime("2011-01-01")); // gives 201152
echo date("YW", strtotime("2011-12-31")); // gives 201152 too
?>
so you can`t rely on number of week given from this function inside your program if you want to use it for some logic
ttt_joe_08 ¶
1 year ago
Just FYI, it's more appropriate to say "UTC", not "GMT". GMT was given up in 1972 and UTC is now the proper way. The reason being G stands for Greenwich, which naturally upset some people.
Jacques Marais ¶
1 year ago
If you want to print something like: Tuesday, the 14th of January, 2014
Use this:
<?php
echo date("l", strtotime("now")).', the'.date(" jS", strtotime("now")).' of'.date(" F, Y", strtotime("now"));
?>
This is because you cannot use words in the date string. If you use words in the date string it will be seen as a format character
So if you use:
<?php
echo date("l, the jS of F, Y", strtotime("now"));
?>
It will print something like: Tuesday, 3108Europe/Berlin 14th 2014f January, 2014
matt ¶
2 years ago
date() has some strange behavior at extremely high values:
<?php
echo "9223372036854775805: " . date("Y-m-d g:i:s a", 9223372036854775805) . "\n";
echo "9223372036854775806: " . date("Y-m-d g:i:s a", 9223372036854775806) . "\n";
echo "9223372036854775807: " . date("Y-m-d g:i:s a", 9223372036854775807) . " (0x7FFFFFFFFFFFFFFF)\n";
echo "9223372036854775808: " . date("Y-m-d g:i:s a", 9223372036854775808) . "\n";
echo "9223372036854775809: " . date("Y-m-d g:i:s a", 9223372036854775809) . "\n";
echo "9223372036854775810: " . date("Y-m-d g:i:s a", 9223372036854775810) . "\n";
echo "...\n";
echo "9223372036854776832: " . date("Y-m-d g:i:s a", 9223372036854776832) . "\n";
echo "9223372036854776833: " . date("Y-m-d g:i:s a", 9223372036854776833) . "\n";
echo "...\n";
echo "9223372036854778879: " . date("Y-m-d g:i:s a", 9223372036854778879) . "\n";
echo "9223372036854778880: " . date("Y-m-d g:i:s a", 9223372036854778880) . "\n";
echo "...\n";
echo "9223372036854780928: " . date("Y-m-d g:i:s a", 9223372036854780928) . "\n";
echo "9223372036854780929: " . date("Y-m-d g:i:s a", 9223372036854780929) . "\n";
echo "...\n";
echo "9223372036854782975: " . date("Y-m-d g:i:s a", 9223372036854782975) . "\n";
echo "9223372036854782976: " . date("Y-m-d g:i:s a", 9223372036854782976) . "\n";
echo "...\n";
echo "9223372036854785024: " . date("Y-m-d g:i:s a", 9223372036854785024) . "\n";
echo "9223372036854785025: " . date("Y-m-d g:i:s a", 9223372036854785025) . "\n";
echo "...\n";
echo "9223372036854787071: " . date("Y-m-d g:i:s a", 9223372036854787071) . "\n";
echo "9223372036854787072: " . date("Y-m-d g:i:s a", 9223372036854787072) . "\n";
echo "...\n";
echo "9223372036854789120: " . date("Y-m-d g:i:s a", 9223372036854789120) . "\n";
echo "9223372036854789121: " . date("Y-m-d g:i:s a", 9223372036854789121) . "\n";
echo "...\n";
echo "9223372036854791167: " . date("Y-m-d g:i:s a", 9223372036854791167) . "\n";
echo "9223372036854791168: " . date("Y-m-d g:i:s a", 9223372036854791168) . "\n";
echo "...\n";
echo "9223372036854793215: " . date("Y-m-d g:i:s a", 9223372036854793215) . "\n";
echo "9223372036854793216: " . date("Y-m-d g:i:s a", 9223372036854793216) . "\n";
echo "9223372036854793217: " . date("Y-m-d g:i:s a", 9223372036854793217) . "\n";
echo "9223372036854793218: " . date("Y-m-d g:i:s a", 9223372036854793218) . "\n";
?>
Output:
9223372036854775805: 292277026596-12-04 10:30:05 am
9223372036854775806: 292277026596-12-04 10:30:06 am
9223372036854775807: 292277026596-12-04 10:30:07 am (0x7FFFFFFFFFFFFFFF)
9223372036854775808: 292277026596-12-04 10:30:08 am
9223372036854775809: 292277026596-12-04 10:30:08 am
9223372036854775810: 292277026596-12-04 10:30:08 am
...
9223372036854778879: 292277026596-12-04 10:30:08 am
9223372036854778880: 292277026596-12-04 11:04:16 am
...
9223372036854778879: 292277026596-12-04 11:04:16 am
9223372036854778880: 292277026596-12-04 11:38:24 am
...
9223372036854780928: 292277026596-12-04 11:38:24 am
9223372036854780929: 292277026596-12-04 12:12:32 pm
...
9223372036854782975: 292277026596-12-04 12:12:32 pm
9223372036854782976: 292277026596-12-04 12:46:40 pm
...
9223372036854785024: 292277026596-12-04 12:46:40 pm
9223372036854785025: 292277026596-12-04 1:20:48 pm
...
9223372036854787071: 292277026596-12-04 1:20:48 pm
9223372036854787072: 292277026596-12-04 1:54:56 pm
...
9223372036854789120: 292277026596-12-04 1:54:56 pm
9223372036854789121: 292277026596-12-04 2:29:04 pm
...
9223372036854791167: 292277026596-12-04 2:29:04 pm
9223372036854791168: 292277026596-12-04 3:03:12 pm
...
9223372036854793215: 292277026596-12-04 3:03:12 pm
9223372036854793216: 292277026596-12-04 3:03:12 pm
9223372036854793217: -292277022657-01-27 8:37:04 am
9223372036854793218: -292277022657-01-27 8:37:04 am
---
So, the last reliable unix timecode is 9223372036854775808 (0x1000000000000000). Not that you would probably ever need a date that high.
Manu Manjunath ¶
10 months ago
If you want to use "u" format specifier for micrseconds without changing to DateTime object, you may write a function as below:
<?php
/**
* Quick replacement to date() function to handle the 'u' format specifier (for microseconds)
* @param string $format Date format string - the same format string you would pass to date() function
* @param float $timestamp [optional] Unix timestamp with microseconds - Typically output of <b>microtime(true)</b>
* @return string Formatted string
*/
function date_with_micro($format, $timestamp = null) {
if (is_null($timestamp) || $timestamp === false) {
$timestamp = microtime(true);
}
$timestamp_int = (int) floor($timestamp);
$microseconds = (int) round(($timestamp - floor($timestamp)) * 1000000.0, 0);
$format_with_micro = str_replace("u", $microseconds, $format);
return date($format_with_micro, $timestamp_int);
}
?>
You can safely replace your date() function with date_with_micro().
