Round minute down to nearest quarter hour

Question

I need to round times down to the nearest quarter hour in PHP. The times are being pulled from a MySQL database from a datetime column and formatted like 2010-03-18 10:50:00.

Example:

• 10:50 needs to be 10:45
• 1:12 needs to be 1:00
• 3:28 needs to be 3:15
• etc.

I'm assuming floor() is involved but not sure how to go about it.

Thanks

Answer 1

It's an old question but having recently implemented myself I'll share my solution:-

public function roundToQuarterHour($datetime) {

    $datetime = ($datetime instanceof DateTime) ? $datetime : new DateTime($datetime);

    return $datetime->setTime($datetime->format('H'), ($i = $datetime->format('i')) - ($i % 15));

}

public function someQuarterHourEvent() {

    print_r($this->roundToQuarterHour(new DateTime()));
    print_r($this->roundToQuarterHour('2016-10-19 10:50:00'));
    print_r($this->roundToQuarterHour('2016-10-19 13:12:00'));
    print_r($this->roundToQuarterHour('2016-10-19 15:28:00'));

}

Answer 2

Here's a function I'm currently using:

/**
 * Rounds a timestamp
 *
 * @param int $input current timestamp
 * @param int $round_to_minutes rounds to this minute
 * @param string $type auto, ceil, floor
 * @return int rounded timestamp
 */
static function roundToClosestMinute($input = 0, $round_to_minutes = 5, $type = 'auto')
{
    $now = !$input ? time() : (int)$input;

    $seconds = $round_to_minutes * 60;
    $floored = $seconds * floor($now / $seconds);
    $ceiled = $seconds * ceil($now / $seconds);

    switch ($type) {
        default:
            $rounded = ($now - $floored < $ceiled - $now) ? $floored : $ceiled;
            break;

        case 'ceil':
            $rounded = $ceiled;
            break;

        case 'floor':
            $rounded = $floored;
            break;
    }

    return $rounded ? $rounded : $input;
}

Hope it helps someone :)

Answer 3

$seconds = time();
$rounded_seconds = round($seconds / (15 * 60)) * (15 * 60);

echo "Original: " . date('H:i', $seconds) . "\n";
echo "Rounded: " . date('H:i', $rounded_seconds) . "\n";

This example gets the current time and rounds it to the nearest quarter and prints both the original and the rounded time.

PS: If you want to round it down replace round() with floor().

Answer 4

$now = getdate();
$minutes = $now['minutes'] - $now['minutes']%15;

 //Can add this to go to the nearest 15min interval (up or down)
  $rmin  = $now['minutes']%15;
  if ($rmin > 7){
    $minutes = $now['minutes'] + (15-$rmin);
   }else{
      $minutes = $now['minutes'] - $rmin;
  }

$rounded = $now['hours'].":".$minutes;
echo $rounded;

Answer 5

Lately I like tackling a problem the TDD/unit testing way. I am not programming much PHP anymore lately, but this is what I came up with. To be honest I actually looked at the code examples here, and picked the one I thought was already correct. Next I wanted to verify this by unit testing using the tests you provided above.

class TimeTest

require_once 'PHPUnit/Framework.php';
require_once 'Time.php';

class TimeTest extends PHPUnit_Framework_TestCase 
{
    protected $time;

    protected function setUp() {
        $this->time = new Time(10, 50);
    }

    public function testConstructingTime() {
        $this->assertEquals("10:50", $this->time->getTime());
        $this->assertEquals("10", $this->time->getHours());
        $this->assertEquals("50", $this->time->getMinutes());        
    }

    public function testCreatingTimeFromString() {
        $myTime = Time::create("10:50");
        $this->assertEquals("10", $myTime->getHours());
        $this->assertEquals("50", $myTime->getMinutes());
    }

    public function testComparingTimes() {
        $timeEquals     = new Time(10, 50);
        $this->assertTrue($this->time->equals($timeEquals));
        $timeNotEquals  = new Time(10, 44);
        $this->assertFalse($this->time->equals($timeNotEquals));
    }


    public function testRoundingTimes()
    {
        // Round test time.
        $roundedTime = $this->time->round();
        $this->assertEquals("10", $roundedTime->getHours());
        $this->assertEquals("45", $roundedTime->getMinutes());

        // Test some more times.
        $timesToTest = array(
            array(new Time(1,00), new Time(1,12)),
            array(new Time(3,15), new Time(3,28)),
            array(new Time(1,00), new Time(1,12)),
        );

        foreach($timesToTest as $timeToTest) {
            $this->assertTrue($timeToTest[0]->equals($timeToTest[0]->round()));
        }        
    }
}

class Time

<?php

class Time
{
    private $hours;
    private $minutes;

    public static function create($timestr) {
        $hours      = date('g', strtotime($timestr));
        $minutes    = date('i', strtotime($timestr));
        return new Time($hours, $minutes);
    }

    public function __construct($hours, $minutes) {
        $this->hours    = $hours;
        $this->minutes  = $minutes;
    }

    public function equals(Time $time) {
        return  $this->hours == $time->getHours() &&
                 $this->minutes == $time->getMinutes();
    }

    public function round() {
        $roundedMinutes = $this->minutes - ($this->minutes % 15);
        return new Time($this->hours, $roundedMinutes);
    }

    public function getTime() {
        return $this->hours . ":" . $this->minutes;
    }

    public function getHours() {
        return $this->hours;
    }

    public function getMinutes() {
        return $this->minutes;
    }
}

Running Test

alfred@alfred-laptop:~/htdocs/time$ phpunit TimeTest.php 
PHPUnit 3.3.17 by Sebastian Bergmann.

....

Time: 0 seconds

OK (4 tests, 12 assertions)

Answer 6

To round nearest quarter hour use below code

<?php
$time = strtotime("01:08");
echo $time.'<br />';
$round = 15*60;
$rounded = round($time / $round) * $round;
echo date("H:i", $rounded);
?>

01:08 become 01:15