ScotlandPHP 2019

DateInterval::__construct

(PHP 5 >= 5.3.0, PHP 7)

DateInterval::__construct新しい DateInterval オブジェクトを作成する

説明

public DateInterval::__construct ( string $interval_spec )

新しい DateInterval オブジェクトを作成します。

パラメータ

interval_spec

間隔。

最初は P から始まります。これは period を表します。 間隔の単位は、整数値の後に間隔指示子をつけて表します。 時間の要素を含む場合は、時間部分の前に文字 T を入れます。

interval_spec の間隔指示子
間隔指示子 説明
Y
M
D
W 週。日付に変換されるので D と組み合わせて使うことはできません。
H 時間
M
S

いくつか簡単な例を示しましょう。 P2D は 2 日、 PT2S は 2 秒、そして P6YT5M は 6 年と 5 分を表します。

注意:

複数の単位を指定するときは、 大きな単位を左、小さな単位を右の順に書かなければなりません。 つまり年は月より先、月は日より先、日は分より先などとなります。 1 年と 4 日を表すのは P1Y4D であり、P4D1Y ではありません。

日付と時刻で間隔を指定することもできます。 1 年と 4 日をこの方式で表すと P0001-00-04T00:00:00 のようになります。 しかし、この方式では繰り返し単位以上の値を指定することはできません (たとえば 25 時間などとは指定できません)。

これらのフォーマットは » ISO 8601 duration specification に基づくものです。

エラー / 例外

interval_spec を間隔としてパースできないときに Exception をスローします。

<?php

$interval 
= new DateInterval('P2Y4DT6H8M');
var_dump($interval);

?>

上の例の出力は以下となります。

object(DateInterval)#1 (8) {
  ["y"]=>
  int(2)
  ["m"]=>
  int(0)
  ["d"]=>
  int(4)
  ["h"]=>
  int(6)
  ["i"]=>
  int(8)
  ["s"]=>
  int(0)
  ["invert"]=>
  int(0)
  ["days"]=>
  bool(false)
}

参考

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User Contributed Notes 13 notes

up
62
owen at beliefs.com
5 years ago
M is used to indicate both months and minutes.

As noted on the referenced wikipedia page for ISO 6801 http://en.wikipedia.org/wiki/Iso8601#Durations

To resolve ambiguity, "P1M" is a one-month duration and "PT1M" is a one-minute duration (note the time designator, T, that precedes the time value).

Using: PHP 5.3.2-1ubuntu4.19

// For 3 Months
$dateTime = new DateTime;echo $dateTime->format( DateTime::ISO8601 ), PHP_EOL;
$dateTime->add(new DateInterval("P3M"));
echo $dateTime->format( DateTime::ISO8601 ), PHP_EOL;
Results in:
2013-07-11T11:12:26-0400
2013-10-11T11:12:26-0400

// For 3 Minutes
$dateTime = new DateTime;echo $dateTime->format( DateTime::ISO8601 ), PHP_EOL;
$dateTime->add(new DateInterval("PT3M"));
echo $dateTime->format( DateTime::ISO8601 ), PHP_EOL;
Results in:
2013-07-11T11:12:42-0400
2013-07-11T11:15:42-0400

Insert a T after the P in the interval to add 3 minutes instead of 3 months.
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11
kevinpeno at gmail dot com
7 years ago
Note that, while a DateInterval object has an $invert property, you cannot supply a negative directly to the constructor similar to specifying a negative in XSD ("-P1Y"). You will get an exception through if you do this.

Instead you need to construct using a positive interval ("P1Y") and the specify the $invert property === 1.
up
17
buvinghausen at gmail dot com
6 years ago
I think it is easiest if you would just use the sub method on the DateTime class.

<?php
$date
= new DateTime();
$date->sub(new DateInterval("P89D"));
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6
jawzx01 at gmail dot com
6 years ago
As previously mentioned, to do a negative DateInterval object, you'd code:

<?php
$date1
= new DateTime();
$eightynine_days_ago = new DateInterval( "P89D" );
$eightynine_days_ago->invert = 1; //Make it negative.
$date1->add( $eightynine_days_ago );
?>

and then $date1 is now 89 days in the past.
up
8
daniellehr at gmx dot de
6 years ago
Alternatively you can use DateInterval::createFromDateString() for negative intervals:

<?php
$date
= new DateTime();
$date->add(DateInterval::createFromDateString('-89 days'));
up
7
admin at torntech dot com
3 years ago
Warning - despite the $interval_spec accepting the ISO 8601 specification format, it does not accept decimal fraction values with period or comma as stated in the specification.

https://bugs.php.net/bug.php?id=53831

<?php
/* Example from ISO 8601 documentation */
$interval = new DateInterval('P0.5Y');
?>

Will result in
Fatal error: Uncaught exception 'Exception' with message 'DateInterval::__construct(): Unknown or bad format (P0.5Y)'
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2
Ray.Paseur sometimes uses Gmail
2 years ago
To recover the interval specification string:

<?php
function get_interval_spec(DateTime $alpha, DateTime $omega)
{
   
$intvl = $alpha->diff($omega);

   
$date = NULL;
    if (
$intvl->y) $date .= $intvl->y . 'Y';
    if (
$intvl->m) $date .= $intvl->m . 'M';
    if (
$intvl->d) $date .= $intvl->d . 'D';

   
$time = NULL;
    if (
$intvl->h) $time .= $intvl->h . 'H';
    if (
$intvl->i) $time .= $intvl->i . 'M';
    if (
$intvl->s) $time .= $intvl->s . 'S';
    if (
$time) $time = 'T' . $time;

   
$text ='P' . $date . $time;
    if (
$text == 'P') return 'PT0S';
    return
$text;
}
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14
kuzb
7 years ago
It should be noted that this class will not calculate days/hours/minutes/seconds etc given a value in a single denomination of time.  For example:

<?php
    $di
= new DateInterval('PT3600S');
    echo
$di->format('%H:%i:%s');
   
?>

will yield 0:0:3600 instead of the expected 1:0:0
up
3
lsloan-php dot net at umich dot edu
2 years ago
Although PHP refers to periods of time as "intervals", ISO 8601 refers to them as "durations".  In ISO 8601, "intervals" are something else.

While ISO 8601 allows fractions for all parts of a duration (e.g., "P0.5Y"), DateInterval does not.  Use caution when calculating durations.  If the duration has a fractional part, it may be lost when storing it in a DateInterval object.
up
1
Hernanibus
1 year ago
It is not stated, but you cannot create directly a negative interval, this is you cannot create a "-2 days" interval as:

<?
$interval = new DateInterval("P-2D");//or
$interval = new DateInterval("-P2D");
?>

Instead you have to create first the interval and then set its 'invert' property to 1, this is:

<?
$interval = new DateInterval("P2D");
$interval->invert = 1;
?>

Then you should keep in mind that this interval acts as a negative number, hence to subtract the interval from a given date you must 'add' it:

<?
$interval = new DateInterval("P2D");
$interval->invert = 1;
$date       = new DateTime ("1978-01-23 17:46:00");
$date->add($interval)->format("Y-m-d H:i:s");//this is "1978-01-21 17:46:00"
?>
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3
userexamplecom at mailinator dot com
2 years ago
Take care, if you have a DateTime Object on the 31h of January and add Da DateInterval of one Month, then you are in March instead of February.

For Example:
---
// given the actual date is 2017-01-31
$today = new DateTime('now', $timeZoneObject);
$today->add(new DateInterval('P1M'));
echo $today->format('m');
// output: 03
---
up
0
sloanlance+php.net gmail com
1 year ago
⚠️ It's important to remember the warning about DateInterval given by "admin at torntech dot com" in an earlier comment (http://php.net/manual/en/dateinterval.construct.php#116750).  To reiterate:

Some versions of PHP (e.g., 5.6.31) have a bug that disallows fractional parts in a ISO 8601 duration string given as the argument for the DateInterval constructor.  That is, these examples will fail:

<?php
// 'P0.5Y' is valid according to ISO 8601
$interval = new DateInterval('P0.5Y');  // Throws exception
?>

<?php
// 'PT585.829S' is valid according to ISO 8601
$interval = new DateInterval('PT585.829S');  // Throws exception
?>

If this bug affects you, please go to the report for this bug in the PHP Bug Tracking System, and place a vote stating that it affects you:  https://bugs.php.net/bug.php?id=53831
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-11
bkilinc at deyta dot net
5 years ago
interval_spec Period Designators, has two 'M's for months and minutes.
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