DateInterval
DateInterval::createFromDateString
DateInterval
PHP Manual

# DateInterval::__construct

Creates a new DateInterval object

### Description

public DateInterval::__construct ( string `$interval_spec` )

Creates a new DateInterval object.

### Parameters

`interval_spec`

  An interval specification.

  The format starts with the letter P, for "period." Each duration period is represented by an integer value followed by a period designator. If the duration contains time elements, that portion of the specification is preceded by the letter T.

  `interval_spec` Period Designators
  Period Designator | Description
  --- | ---
  Y | years
  M | months
  D | days
  W | weeks. These get converted into days, so can not be combined with D.
  H | hours
  M | minutes
  S | seconds

  Here are some simple examples. Two days is P2D. Two seconds is PT2S. Six years and five minutes is P6YT5M.

  > Note:

  > The unit types must be entered from the largest scale unit on the left to the smallest scale unit on the right. So years before months, months before days, days before minutes, etc. Thus one year and four days must be represented as P1Y4D, not P4D1Y.

  The specification can also be represented as a date time. A sample of one year and four days would be P0001-00-04T00:00:00. But the values in this format can not exceed a given period's roll-over-point (e.g. 25 hours is invalid).

  These formats are based on the » ISO 8601 duration specification.

### Errors/Exceptions

Throws an Exception when the `interval_spec` cannot be parsed as an interval.

### Examples

Example #1 DateInterval example

`<?php
$interval = new DateInterval('P2Y4DT6H8M');
var_dump($interval);
?>`

The above example will output:

    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)
    }

### See Also

- DateInterval::format
- DateTime::add
- DateTime::sub
- DateTime::diff