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DateTime::format> <DateTime::createFromFormat
[edit] Last updated: Fri, 25 May 2012

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DateTime::diff

date_diff

(PHP 5 >= 5.3.0)

DateTime::diff -- date_diffふたつの DateTime オブジェクトの差を返す

説明

オブジェクト指向型

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

手続き型

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

ふたつの DateTime オブジェクトの差を返します。

パラメータ

datetime

比較する日付。

absolute

差の絶対値を返すか否か。

返り値

ふたつの日付の差をあらわす DateInterval オブジェクトを返します。 失敗した場合に FALSE を返します

例1 DateTime::diff() の例

オブジェクト指向型

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

手続き型

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

上の例の出力は以下となります。

+2 days

例2 DateTime オブジェクトの比較

注意:

PHP 5.2.2 以降では、DateTime オブジェクトを 比較演算子 で比較できるようになりました。

<?php
$date1 
= new DateTime("now");
$date2 = new DateTime("tomorrow");

var_dump($date1 == $date2);
var_dump($date1 $date2);
var_dump($date1 $date2);
?>

上の例の出力は以下となります。

bool(false)
bool(true)
bool(false)

参考



DateTime::format> <DateTime::createFromFormat
[edit] Last updated: Fri, 25 May 2012
 
add a note add a note User Contributed Notes DateTime::diff
sgmurphy19 08-Feb-2012 11:00
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" ) );
}
?>
toreskobba at gmail dot com 10-Nov-2011 03:24
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');
astagl at gmail dot com 09-Nov-2011 08:21
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.
Anonymous 03-Oct-2011 08:12
$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 ...
milespickens+php at gmail dot com 16-May-2011 03:00
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
?>
Grgoire Marchal 18-Feb-2011 02:22
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
schindhelm at gmail dot com 21-Jan-2011 12:48
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.
Umair Ashraf 21-Nov-2010 11:49
for PHP version 5.3

<?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;
}
?>

for PHP version 5.2

<?php
public function ago($dt)
{
   
$dt = date_parse($dt);
   
$now = date_parse(date("Y-m-d H:i:s"));
       
   
$suffix = " ago";
       
    if (
$now['year'] != $dt['year']) return $this->pluralize($now['year'] - $dt['year'], "year") . $suffix;
    if (
$now['month'] != $dt['month']) return $this->pluralize($now['month'] - $dt['month'], "month") . $suffix;
    if (
$now['day'] != $dt['day']) return $this->pluralize($now['day'] - $dt['day'], "day") . $suffix;
    if (
$now['hour'] != $dt['hour']) return $this->pluralize($now['hour'] - $dt['hour'], "hour") . $suffix;
    if (
$now['minute'] != $dt['minute']) return $this->pluralize($now['minute'] - $dt['minute'], "minute") . $suffix;
    if (
$now['second'] != $dt['second']) return $this->pluralize($now['second'] - $dt['second'], "second") . $suffix;
        return
"just now";
}

private function
pluralize($count, $text)
{
    return
$count . (($count == 1) ? (" $text") : (" ${text}s"));
}
?>
acrion at gmail dot com 13-May-2010 08:52
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;
}
?>
Dennis C 09-May-2010 11:24
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 \>");
?>
Anonymous 04-Aug-2009 05:17
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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