DateTime::diff

(PHP 5 >= 5.3.0)

DateTime::diffبازگرداندن تفاوت بین دو شی DateTime

Description

Oriented object style

public DateInterval DateTime::diff ( DateTime $datetime2 [, bool $absolute = false ] )

Procedural style

DateInterval date_diff ( DateTime $datetime1 , DateTime $datetime2 [, bool $absolute = false ] )

بازگرداندن تفاوت بین دو شی DateTime.

Parameters

datetime

تاریخ برای مقایسه.

absolute

آیا تفاوت مطلق بازگردانده شود.

Return Values

شی DateInterval نمایش‌دهنده تفاوت بین دو شی or FALSE on failure.

Examples

Example #1 مثال DateTime::diff()

Oriented object style

<?php
$datetime1 
= new DateTime('2009-10-11');
$datetime2 = new DateTime('2009-10-13');
$interval $datetime1->diff($datetime2);
echo 
$interval->format('%R%d days');
?>

Procedural style

<?php
$datetime1 
date_create('2009-10-11');
$datetime2 date_create('2009-10-13');
$interval date_diff($datetime1$datetime2);
echo 
$interval->format('%R%d days');
?>

The above examples will output:

+2 days

See Also

  • DateInterval::format() - Formats the interval
  • DateTime::add() - اصافه کردن تعداد روز، ماه، سال، ساعت، دقیقه و ثانیه به شی DateTime
  • DateTime::sub() - کم کردن تعدادی روز، ماه، سال، ساعت، دقیقه و ثانیه به شی DateTime
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User Contributed Notes 17 notes

up
12
ianlenmac at gmail dot com
7 months ago
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.
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11
sgmurphy19
2 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" ) );
}
?>
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5
schindhelm at gmail dot com
3 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.
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6
Dennis C
3 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 \>");
?>
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2
Grgoire Marchal
3 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
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3
Anonymous
4 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)
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3
astagl at gmail dot com
2 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.
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2
gusarov at ukr.net
10 months 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";
?>
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1
acrion at gmail dot com
3 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;
}
?>
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1
amons dot 360 at gmail dot com
1 year 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
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0
nospam at oece dot me
3 days 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
?>
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0
crayonviolent at phpfreaks dot com
1 month 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";
?>
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0
milespickens+php at gmail dot com
2 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
?>
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-1
radu dot potop at wooptoo dot com
1 year ago
Keep in mind that diff will convert the two DateTime objects from local time to UTC.
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-1
php at jcouture dot net
10 months 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]
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-3
Anonymous
2 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 ...
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-2
toreskobba at gmail dot com
2 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');
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