DateInterval::format

(PHP 5 >= 5.3.0, PHP 7)

Formats the interval

public string DateInterval::format ( string $format )

Formats the interval.

Parameters:

format

**The following characters are recognized in the `format` parameter string. Each format character must be prefixed by a percent sign (%).**
`format` character	Description	Example values
%	Literal %	%
Y	Years, numeric, at least 2 digits with leading 0	01, 03
y	Years, numeric	1, 3
M	Months, numeric, at least 2 digits with leading 0	01, 03, 12
m	Months, numeric	1, 3, 12
D	Days, numeric, at least 2 digits with leading 0	01, 03, 31
d	Days, numeric	1, 3, 31
a	Total number of days as a result of a DateTime::diff() or (unknown) otherwise	4, 18, 8123
H	Hours, numeric, at least 2 digits with leading 0	01, 03, 23
h	Hours, numeric	1, 3, 23
I	Minutes, numeric, at least 2 digits with leading 0	01, 03, 59
i	Minutes, numeric	1, 3, 59
S	Seconds, numeric, at least 2 digits with leading 0	01, 03, 57
s	Seconds, numeric	1, 3, 57
R	Sign "-" when negative, "+" when positive	-, +
r	Sign "-" when negative, empty when positive	-,

Returns:

Returns the formatted interval.

Notes:

The DateInterval::format() method does not recalculate carry over points in time strings nor in date segments. This is expected because it is not possible to overflow values like "32 days" which could be interpreted as anything from "1 month and 4 days" to "1 month and 1 day".

Examples:

DateInterval example

<?php
 
$interval = new DateInterval('P2Y4DT6H8M');
echo $interval->format('%d days');
 
?>

The above example will output:

4 days

DateInterval and carry over points

<?php
 
$interval = new DateInterval('P32D');
echo $interval->format('%d days');
 
?>

The above example will output:

32 days

DateInterval and DateTime::diff() with the %a and %d modifiers

<?php
 
$january = new DateTime('2010-01-01');
$february = new DateTime('2010-02-01');
$interval = $february->diff($january);
 
// %a will output the total number of days.
echo $interval->format('%a total days')."\n";
 
// While %d will only output the number of days not already covered by the
// month.
echo $interval->format('%m month, %d days');
 
?>

The above example will output:

31 total days
1 month, 0 days