How to get the first day of the current year?

Question

I need to use PHP DateTime to get the first day of the current year. I\'ve tried:

$year = new DateTime(\'first day of this year\');
var_dump($year);
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Answer 1

Basically date('Y') returns the value of current year. and the first day of each year starts like 2000-01-01.

so this will help you to get exact output.

$firstdate = date('Y').'01-01';

Answer 2

As a commenter @Glavić said already

$year = new DateTime('first day of January');

is the solution.

To me it did make sense semantically that "this year" should return midnight of the first day of the year, but indeed it does not!

Answer 3

Just wanted to record some nuance with the answer by lorem monkey

The suggested method might cause issues with when using time zones.

scenario: consider current system time is 2018-01-01 00:20:00 UTC and system default time zone is set to UTC.

date('Y') will give you 2018

if you are doing something like:

$startDate = new DateTime('first day of january '.date('Y'), new DateTimeZone('America/New_York'));

This will compute to 'first day of january 2018' but you actually needed the first date of your current year in America/New_York, which is still 2017.

Stop dropping the ball man, its not new year yet!

So it is better to just do

$startDate = new DateTime('first day of january', new DateTimeZone('America/New_York'));

And then do the modifications as needed by using the DateTime::modify() function.

Relative date formats are fun.

My scenario: I wanted to get the bounds of this year as in 2018-01-01 00:00:00 to 2018-12-31 23:59:59

This can be achieved in two ways with relative date formats.

one way is to use the DateTime::modify() function on the object.

$startDate = (new DateTime('now', new DateTimeZone("America/New_York")));
$endDate = (new DateTime('now', new DateTimeZone("America/New_York")));

$startDate->modify("january")
    ->modify("first day of this month")
    ->modify("midnight");
    
$endDate->modify("next year")
    ->modify("january")
    ->modify("first day of this month")
    ->modify("midnight")->modify("-1 second");

var_dump([$startDate, $endDate]);

Try out here: https://www.tehplayground.com/Qk3SkcrCDkNJoLK2

Another way to do this is to separate the relative strings with a comma like so:

$startDate = (new DateTime('first day of january', new DateTimeZone("America/New_York")));
$endDate = (new DateTime('next year, first day of january, -1 second', new DateTimeZone("America/New_York")));
var_dump([$startDate, $endDate]);

Try out here: https://www.tehplayground.com/hyCqXLRBlhJbCyks

Answer 4

Take a look at this link -- http://davidhancock.co/2013/11/get-the-firstlast-day-of-a-week-month-quarter-or-year-in-php/

 function firstDayOf($period, DateTime $date = null)
{
    $period = strtolower($period);
    $validPeriods = array('year', 'quarter', 'month', 'week');

    if ( ! in_array($period, $validPeriods))
        throw new InvalidArgumentException('Period must be one of: ' . implode(', ', $validPeriods));

    $newDate = ($date === null) ? new DateTime() : clone $date;

    switch ($period) {
        case 'year':
            $newDate->modify('first day of january ' . $newDate->format('Y'));
            break;
        case 'quarter':
            $month = $newDate->format('n') ;

            if ($month < 4) {
                $newDate->modify('first day of january ' . $newDate->format('Y'));
            } elseif ($month > 3 && $month < 7) {
                $newDate->modify('first day of april ' . $newDate->format('Y'));
            } elseif ($month > 6 && $month < 10) {
                $newDate->modify('first day of july ' . $newDate->format('Y'));
            } elseif ($month > 9) {
                $newDate->modify('first day of october ' . $newDate->format('Y'));
            }
            break;
        case 'month':
            $newDate->modify('first day of this month');
            break;
        case 'week':
            $newDate->modify(($newDate->format('w') === '0') ? 'monday last week' : 'monday this week');
            break;
    }

    return $newDate;
}

Answer 5

Or use only text in the strtotime function:

date('Y-m-d', strtotime('first day of january this year'));

Answer 6

in PHP 5.3.10 this works

$myDate = new \DateTime(date("Y")."-01-01");                                                                                                                                                                        
echo $myDate->format("Y-m-d");

In PHP 5.4 and upper you can put all together

echo (new \DateTime(date("Y")."-01-01"))->format("Y-m-d")