It is worth noting, IMO, and it is implied in the docs but not explicitly stated, that the object on which diff is called is subtracted from the object that is passed to diff.
i.e. $now->diff($tomorrow) is positive.
PHP - Manual: DateTime::diff
2024-04-30
DateTime::diff
DateTimeImmutable::diff
DateTimeInterface::diff
date_diff
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
DateTime::diff -- DateTimeImmutable::diff -- DateTimeInterface::diff -- date_diff — Returns the difference between two DateTime objects
说明
面向对象风格
public DateTimeImmutable::diff(DateTimeInterface
$targetObject, bool $absolute = false): DateIntervalpublic DateTimeInterface::diff(DateTimeInterface
$targetObject, bool $absolute = false): DateInterval过程化风格
date_diff(DateTimeInterface
$baseObject, DateTimeInterface $targetObject, bool $absolute = false): DateIntervalReturns the difference between two DateTimeInterface objects.
参数
-
datetime -
The date to compare to.
-
absolute -
Should the interval be forced to be positive?
返回值
The DateInterval object represents the
difference between the two dates 或者在失败时返回 false.
The return value more specifically represents the interval to apply to the
original object ($this or
$originObject) to arrive at the
$targetObject. This process is not always
reversible.
范例
示例 #1 DateTime::diff() example
面向对象风格
<?php
$origin = new DateTime('2009-10-11');
$target = new DateTime('2009-10-13');
$interval = $origin->diff($target);
echo $interval->format('%R%a days');
?>
过程化风格
<?php
$origin = date_create('2009-10-11');
$target = date_create('2009-10-13');
$interval = date_diff($origin, $target);
echo $interval->format('%R%a days');
?>
以上例程会输出：
+2 days
示例 #2 DateTime object comparison
注意:
DateTime objects can be compared using comparison operators.
<?php
$date1 = new DateTime("now");
$date2 = new DateTime("tomorrow");
var_dump($date1 == $date2);
var_dump($date1 < $date2);
var_dump($date1 > $date2);
?>
以上例程会输出：
bool(false) bool(true) bool(false)
参见
- DateInterval::format() - Formats the interval
- DateTime::add() - 给一个 DateTime 对象增加一定量的天，月，年，小时，分钟 以及秒。
- DateTime::sub() - 对一个 DateTime 对象减去一定量的 日、月、年、小时、分钟和秒。
add a note
User Contributed Notes 31 notes
ianlenmac at gmail dot com ¶
8 years ago
steve at portable dot com dot au ¶
3 months ago
There is an interesting quirk around leap days. If the first date is a leap date (29th February in a leap year) and the second date is not a leap year, the results may not be what you expect:
<?php
$tz = new DateTimeZone('UTC');
$dt1 = new DateTime('2012-02-29 13:00:00', $tz);
$dt2 = new DateTime('2013-03-01 12:00:00', $tz);
print $dt1->diff($dt2)->format('%r%y years, %m months, %d days, %h hours, %i minutes, %s seconds');
/* Output:
0 years, 11 months, 30 days, 23 hours, 0 minutes, 0 seconds
*/
?>
If you reverse the order of the dates you get:
<?php
print $dt2->diff($dt1)->format('%r%y years, %m months, %d days, %h hours, %i minutes, %s seconds');
/* Output:
-1 years, 0 months, 0 days, 23 hours, 0 minutes, 0 seconds
*/
?>
cagatay at devmonks dot net ¶
6 years ago
Be careful using:
$date1 = new DateTime('now');
$date2 = new DateTime('tomorrow');
$interval = date_diff($date1, $date2);
echo $interval->format('In %a days');
In some situations, this won't say "in 1 days", but "in 0 days".
I think this is because "now" is the current time, while "tomorrow" is the current day +1 but at a default time, lets say:
Now: 08:00pm, 01.01.2015
Tomorrow: 00:00am, 02.01.2015
In this case, the difference is not 24 hour, so it will says 0 days.
Better use "today", which should also use a default value like:
Today: 00:00am, 01.01.2015
Tomorrow: 00:00am, 02.01.2015
which now is 24 hour and represents 1 day.
This may sound logical and many will say "of course, this is right", but if you use it in a naiv way (like I did without thinking), you can come to this moment and facepalm yourself.
Conclusion: "Now" is "Today", but in a different clock time, but still the same day!
php at jcouture dot net ¶
9 years ago
After wrestling with DateTime::diff for a while it finally dawned on me the problem was both in the formatting of the input string and the formatting of the output.
The task was to calculate the duration between two date/times.
### Calculating Duration
1. Make sure you have a valid date variable. Both of these strings are valid:
<?php
// Example
$strStart = '2013-06-19 18:25';
$strEnd = '06/19/13 21:47';
?>
2. Next convert the string to a date variable
~~~
<?php
$dteStart = new DateTime($strStart);
$dteEnd = new DateTime($strEnd);
?>
~~~
3. Calculate the difference
~~~
<?php
$dteDiff = $dteStart->diff($dteEnd);
?>
~~~
4. Format the output
~~~
<?php
print $dteDiff->format("%H:%I:%S");
/*
Outputs
03:22:00
*/
?>
~~~
[Modified by moderator for clarify]
nospam at oece dot me ¶
8 years ago
Using the identical (===) comparision operator in different but equal objects will return false
<?php
$c = new DateTime( '2014-04-20' );
$d = new DateTime( '2014-04-20' );
var_dump( $d === $d ); #true
var_dump( $d === $c ); #false
var_dump( $d == $c ); #true
?>
acrion at gmail dot com ¶
12 years ago
If you want to quickly scan through the resulting intervals, you can use the undocumented properties of DateInterval.
The function below returns a single number of years, months, days, hours, minutes or seconds between the current date and the provided date. If the date occurs in the past (is negative/inverted), it suffixes it with 'ago'.
<?php
function pluralize( $count, $text )
{
return $count . ( ( $count == 1 ) ? ( " $text" ) : ( " ${text}s" ) );
}
function ago( $datetime )
{
$interval = date_create('now')->diff( $datetime );
$suffix = ( $interval->invert ? ' ago' : '' );
if ( $v = $interval->y >= 1 ) return pluralize( $interval->y, 'year' ) . $suffix;
if ( $v = $interval->m >= 1 ) return pluralize( $interval->m, 'month' ) . $suffix;
if ( $v = $interval->d >= 1 ) return pluralize( $interval->d, 'day' ) . $suffix;
if ( $v = $interval->h >= 1 ) return pluralize( $interval->h, 'hour' ) . $suffix;
if ( $v = $interval->i >= 1 ) return pluralize( $interval->i, 'minute' ) . $suffix;
return pluralize( $interval->s, 'second' ) . $suffix;
}
?>
crayonviolent at phpfreaks dot com ¶
8 years ago
It seems that while DateTime in general does preserve microseconds, DateTime::diff doesn't appear to account for it when comparing.
Example:
<?php
$val1 = '2014-03-18 10:34:09.939';
$val2 = '2014-03-18 10:34:09.940';
$datetime1 = new DateTime($val1);
$datetime2 = new DateTime($val2);
echo "<pre>";
var_dump($datetime1->diff($datetime2));
if($datetime1 > $datetime2)
echo "1 is bigger";
else
echo "2 is bigger";
?>
The var_dump shows that there is no "u" element, and "2 is bigger" is echoed.
To work around this apparent limitation/oversight, you have to additionally compare using DateTime::format.
Example:
<?php
if($datetime1 > $datetime2)
echo "1 is bigger";
else if ($datetime1->format('u') > $datetime2->format('u'))
echo "1 is bigger";
else
echo "2 is bigger";
?>
astagl at gmail dot com ¶
10 years ago
I needed to get the exact number of days between 2 dates and was relying on the this diff function, but found that I was getting a peculiar result with:
<?php
$today = new DateTime(date('2011-11-09'));
$appt = new DateTime(date('2011-12-09'));
$days_until_appt = $appt->diff($today)->d;
?>
This was returning 0 because it was exactly one month.
I had to end up using :
<?php
$days_until_appt = $appt->diff($today)->days;
?>
to get 30.
csongor at halmai dot hu ¶
5 years ago
Be careful, the behaviour depends on the time zones in a weird way.
<?php
function printDiff($tz) {
$d1 = new DateTime("2015-06-01", new DateTimeZone($tz));
$d2 = new DateTime("2015-07-01", new DateTimeZone($tz));
$diff = $d1->diff($d2);
print($diff->format("Year: %Y Month: %M Day: %D"). PHP_EOL);
}
printDiff("UTC");
printDiff("Australia/Melbourne");
?>
The result is different:
Year: 00 Month: 01 Day: 00
Year: 00 Month: 00 Day: 30
sgmurphy19 ¶
10 years ago
Though I found a number of people who ran into the issue of 5.2 and lower not supporting this function, I was unable to find any solid examples to get around it. Therefore I hope this can help some others:
<?php
function get_timespan_string($older, $newer) {
$Y1 = $older->format('Y');
$Y2 = $newer->format('Y');
$Y = $Y2 - $Y1;
$m1 = $older->format('m');
$m2 = $newer->format('m');
$m = $m2 - $m1;
$d1 = $older->format('d');
$d2 = $newer->format('d');
$d = $d2 - $d1;
$H1 = $older->format('H');
$H2 = $newer->format('H');
$H = $H2 - $H1;
$i1 = $older->format('i');
$i2 = $newer->format('i');
$i = $i2 - $i1;
$s1 = $older->format('s');
$s2 = $newer->format('s');
$s = $s2 - $s1;
if($s < 0) {
$i = $i -1;
$s = $s + 60;
}
if($i < 0) {
$H = $H - 1;
$i = $i + 60;
}
if($H < 0) {
$d = $d - 1;
$H = $H + 24;
}
if($d < 0) {
$m = $m - 1;
$d = $d + get_days_for_previous_month($m2, $Y2);
}
if($m < 0) {
$Y = $Y - 1;
$m = $m + 12;
}
$timespan_string = create_timespan_string($Y, $m, $d, $H, $i, $s);
return $timespan_string;
}
function get_days_for_previous_month($current_month, $current_year) {
$previous_month = $current_month - 1;
if($current_month == 1) {
$current_year = $current_year - 1; //going from January to previous December
$previous_month = 12;
}
if($previous_month == 11 || $previous_month == 9 || $previous_month == 6 || $previous_month == 4) {
return 30;
}
else if($previous_month == 2) {
if(($current_year % 4) == 0) { //remainder 0 for leap years
return 29;
}
else {
return 28;
}
}
else {
return 31;
}
}
function create_timespan_string($Y, $m, $d, $H, $i, $s)
{
$timespan_string = '';
$found_first_diff = false;
if($Y >= 1) {
$found_first_diff = true;
$timespan_string .= pluralize($Y, 'year').' ';
}
if($m >= 1 || $found_first_diff) {
$found_first_diff = true;
$timespan_string .= pluralize($m, 'month').' ';
}
if($d >= 1 || $found_first_diff) {
$found_first_diff = true;
$timespan_string .= pluralize($d, 'day').' ';
}
if($H >= 1 || $found_first_diff) {
$found_first_diff = true;
$timespan_string .= pluralize($H, 'hour').' ';
}
if($i >= 1 || $found_first_diff) {
$found_first_diff = true;
$timespan_string .= pluralize($i, 'minute').' ';
}
if($found_first_diff) {
$timespan_string .= 'and ';
}
$timespan_string .= pluralize($s, 'second');
return $timespan_string;
}
function pluralize( $count, $text )
{
return $count . ( ( $count == 1 ) ? ( " $text" ) : ( " ${text}s" ) );
}
?>
Grgoire Marchal ¶
11 years ago
Warning, there's a bug on windows platforms: the result is always 6015 days (and not 42...)
http://bugs.php.net/bug.php?id=51184
anonymous ¶
1 year ago
<?php
$date1 = new DateTime('2015-06-22T10:40:25', new DateTimeZone('Europe/London'));
$date2 = new DateTime("2010-01-01 22:10:57",new DateTimeZone('Asia/Kathmandu'));
$interval = date_diff($date1, $date2);
print $interval->format("Days = %a Time = %H:%I:%S .");
?>
toreskobba at gmail dot com ¶
10 years ago
When using datediff make sure your time zone is correct, for me on Windows 7 64 bit it behaved very strange when timezone was wrong (I was comparing now against time in database and exif metadata in photos). For example: date_default_timezone_set('Europe/Oslo');
Dennis C ¶
12 years ago
For those like me who don't yet have PHP 5.3 installed on their host, here's a simple alternative to get the number of days between two dates in the format '2010-3-23' or similar acceptable to strtotime(). You need PHP 5.2.
<?php
function date_diff($date1, $date2) {
$current = $date1;
$datetime2 = date_create($date2);
$count = 0;
while(date_create($current) < $datetime2){
$current = gmdate("Y-m-d", strtotime("+1 day", strtotime($current)));
$count++;
}
return $count;
}
echo (date_diff('2010-3-9', '2011-4-10')." days <br \>");
?>
sloanlance+php dot net at gmail dot com ¶
4 years ago
When getting the difference between two DateTime objects with fractions of seconds, DateTime::diff() works under PHP 7.1. However, under PHP 5.6, the fraction is truncated. It's not clear whether the truncation happens when getting the DateTime objects' values, during the calculation, or immediately before returning the result.
schindhelm at gmail dot com ¶
11 years ago
I found that DateTime::diff isn't as accurate as I thought. I calculated the age gap between now and a birthdate from before 1970 (unix epoch). Here's what I got:
Given today is January 21st, 2011:
<?php
date_default_timezone_set('Europe/Berlin');
// birthdate format is YYYY-MM-DD
$birth = new DateTime('1966-01-21');
$today = new DateTime();
$diff = $birth->diff($today);
echo $diff->format('%y'); // will output 45
$birth = new DateTime('1966-01-23');
$today = new DateTime();
$diff = $birth->diff($today);
echo $diff->format('%y'); // will output 45 wrongly
$birth = new DateTime('1966-01-24'); // three days difference!
$today = new DateTime();
$diff = $birth->diff($today);
echo $diff->format('%y'); // will output 44 - correct
?>
When calculating with the date() function it was more accurate (didn't use seconds/hours for comparison).
Note that 3 days may be a lot if you want to create invoices and have to check against a given age to determine if the customer is chargable for taxes and so on.
If someone also found this behaviour I'd like to hear about it - give me a quick mail at schindhelm (at) gmail (dot) com.
Thanks.
milespickens+php at gmail dot com ¶
11 years ago
I was looking for a way to output X number of days from a given date and didn't find exactly what I was looking for. But I got this working. I hope this helps you.
This will output the number of days,months, or years difference between NOW and a April 1st, 2011.
<?php
$date1 = new DateTime('2011-04-01');
$date2 = new DateTime("now");
$interval = $date1->diff($date2);
$years = $interval->format('%y');
$months = $interval->format('%m');
$days = $interval->format('%d');
if($years!=0){
$ago = $years.' year(s) ago';
}else{
$ago = ($months == 0 ? $days.' day(s) ago' : $months.' month(s) ago');
}
echo $ago;
?>
If I used today, 2011-05-16 as $date1, I could return all 0's in the format. For example....
<?php
$date1 = new DateTime('2011-05-161');
$date2 = new DateTime("now");
$interval = $date1->diff($date2);
$diff = $interval->format('%y-%m-%d');
echo $diff; //Today, this will output 0-0-0
?>
wildpenguin at gmail dot com ¶
4 years ago
Be careful when using the difference between 'Now' and a future value.
Example:
// imagine it is 2018-04-20
$date1 = new DateTime('now');
$date2 = new DateTime(date('Y-m-d'));
$date3 = new DateTime("2018-04-30"); // future
echo $date1->diff($date3)->days; // 9 days
echo $date2->diff($date3)->days; // 10 days
radu dot potop at wooptoo dot com ¶
9 years ago
Keep in mind that diff will convert the two DateTime objects from local time to UTC.
amons dot 360 at gmail dot com ¶
9 years ago
So this function is not available for my server's PHP. I created an alternative.
Convert the datetime into time-stamps, then subtract normally, then convert the seconds to whatever you want.
<?
$date1 = new DateTime('now');
$date1->modify("-3 hours");
$date2 = new DateTime('now');
$number1 = (int)$date1->format('U');
$number2 = (int)$date2->format('U');
echo ($number2 - $number1)/60/60; // will print 3
?>
-Suleiman ALAQEL
gusarov at ukr.net ¶
9 years ago
for php<5.3
<?php
$date1 = strtotime('2013-07-03 18:00:00');
$date2 = time();
$subTime = $date1 - $date2;
$y = ($subTime/(60*60*24*365));
$d = ($subTime/(60*60*24))%365;
$h = ($subTime/(60*60))%24;
$m = ($subTime/60)%60;
echo "Difference between ".date('Y-m-d H:i:s',$date1)." and ".date('Y-m-d H:i:s',$date2)." is:\n";
echo $y." years\n";
echo $d." days\n";
echo $h." hours\n";
echo $m." minutes\n";
?>
Anonymous ¶
12 years ago
You don't need to calculate the exact difference if you just want to know what date comes earlier:
<?php
date_default_timezone_set('Europe/Madrid');
$d1 = new DateTime('1492-01-01');
$d2 = new DateTime('1492-12-31');
var_dump($d1 < $d2);
var_dump($d1 > $d2);
var_dump($d1 == $d2);
?>
bool(true)
bool(false)
bool(false)
Anonymous ¶
5 years ago
<?php
$datetime1 = new DateTime('2016-11-30');
$datetime2 = new DateTime('2017-03-01');
$interval = $datetime1->diff($datetime2);
var_dump($interval->days / 30.4375);
$month = $interval->m + $interval->y * 12;
var_dump($month);
Result:
float(2.9897330595483)
int(2) <-- Where is the third month? February has 28/29 days total.
For
<?php
$datetime1 = new DateTime('2016-11-30');
$datetime2 = new DateTime('2017-03-02');
Result:
float(3.0225872689938)
int(3)
monirul ¶
2 years ago
$strStart = '2013-06-19 18:25';
$strEnd = '06/21/13 21:47';
$dteStart = new DateTime($strStart);
$dteEnd = new DateTime($strEnd);
$dteDiff = $dteStart->diff($dteEnd);
print $dteDiff->format("%H:%I:%S");
this script not comparing the date, its working only for the time
starsniper at in dot com ¶
8 years ago
Another Method to compare dates:
<?php
$d1 = new DateTime('2014-06-07 20:56:00');
$d2 = new DateTime('2014-06-09 21:09:00');
echo 'The DateTimes are: <br /> d1: '.$d1->format("d-M-y, h:i A").'<br /> d2: '.$d2->format("d-M-y, h:i A");
$date_diff = $d1->diff($d2); // difference of dates = ($d2 - $d1)
if ( (int)$date_diff->format('%R%a') >= 0 ){
echo '<br /><br />The recent date is: '.$d2->format("d-M-y, h:i A");
echo '<br /> The older date is: '.$d1->format("d-M-y, h:i A");
}else{
echo '<br /><br />The recent date is: '.$d1->format("d-M-y, h:i A");
echo '<br /> The older date is: '.$d2->format("d-M-y, h:i A");
}
?>
Output:
The DateTimes are:
d1: 07-Jun-14, 08:56 PM
d2: 09-Jun-14, 09:09 PM
The recent date is: 09-Jun-14, 09:09 PM
The older date is: 07-Jun-14, 08:56 PM
arunajamal at yahoo dot com ¶
6 years ago
Similar to what was mentioned by ianlenmac at gmail dot com
I think its also worth mentioning to note that date_diff($datetime1, $datetime2) is equivalent to " subtract $datetime1 from $datetime2 " as opposed to thinking otherwise because of the arrangement of the arguments
so date_diff($now, $tomorrow) is +ve
devegpat at gmail dot com ¶
6 years ago
<?PHP
/*small script to check if the given date is between the limit
$gap is the limit needed
date format taken is d-m-yyyy
using PDO
*/
date_default_timezone_set('Asia/kolkata');
$gap = 60;
$givendate = '7-9-2015';
$givendate = explode('-', $givendate);
$thisday = $givendate[0];
$thismonth = $givendate[1];
$thisyear = $givendate[2];
$date1 = new DateTime(date('d-m-Y',mktime(0,0,0,$thismonth,$thisday,$thisyear)));
$date2 = new DateTime(date('d-m-Y'));
$differ = $date1->diff($date2);
$daysbetween = $differ->format('%a');
echo $daysbetween;
if($daysbetween > $gap){
printf("Enter a date within next %d days the difference is %d",$gap,$daysbetween);
}
else{
printf("Date is valid and difference is %d",$daysbetween);
}
?>
Daniel Klein ¶
5 years ago
WARNING!!!
Although you CAN directly compare DateTime objects, you will get nonintuitive results if the other object is not also DateTime compatible.
I just found a subtle bug in my code because it was comparing a date against an uninitialised variable.
<?php
$now = new DateTime();
$other_date = null;
var_dump($now < $other_date); // false
var_dump($now > $other_date); // true
?>
It's better to use DateTime::diff() because the return value will only be a DateInterval object if the types were compatible, otherwise it will be false.
<?php
$then = new DateTime('yesterday');
$now = new DateTime();
$other_date = null;
var_dump($now->diff($other_date)); // false
var_dump($now->diff($then)); // DateInterval object
?>
If a DateInterval object was returned, you can check the 'invert' property to see if the second date is before the first date or not. DateInterval::invert will be 1 if the second date is before the first date, and 0 if the the second date is on or after the first date.
Anonymous ¶
10 years ago
$dateTime = new DateTime('2011-08-01 00:00:00');
echo $dateTime->diff(new DateTime('2011-10-01 00:00:01'))->format('%m');
will return 1, instead of 2 ...
qrworld.net ¶
7 years ago
Here you have in this post http://softontherocks.blogspot.com/2014/12/calcular-la-edad-con-php.html the code to get the age of a person specifying the date of birth:
function getAge($birthdate){
$adjust = (date("md") >= date("md", strtotime($birthdate))) ? 0 : -1; // Si aún no hemos llegado al día y mes en este año restamos 1
$years = date("Y") - date("Y", strtotime($birthdate)); // Calculamos el número de años
return $years + $adjust; // Sumamos la diferencia de años más el ajuste
}
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