how to set 00:00:00 for DateTime

Question

What I want to get are

• today's 00:00:00
• week start day's 00:00:00
• month start day's 00:00:00
• year start day's 00:00:00

So I write the code,

$today = new \DateTime();
$weekStart = new \DateTime();
$monthStart = new \DateTime();
$yearStart = new \DateTime();

$weekStart->modify('last sunday');
$monthStart->modify('first day of this months');
$yearStart->modify('first day of this year');

print $today->format('Y-m-d h:i:s')."\n";
print $weekStart->format('Y-m-d h:i:s')."\n";
print $monthStart->format('Y-m-d h:i:s')."\n";
print $yearStart->format('Y-m-d h:i:s')."\n";

It gave me the result:

2018-11-13 09:34:02
2018-11-11 12:00:00
2018-11-01 09:34:02
2018-11-01 09:34:02

I have two questions.

How can I make each DateTime 00:00:00??

How can I get the first day of year???

Answer 1

PHP's date parsing is somewhat tricky. Here's the code snippet which does what you want:

$today = new \DateTime('midnight');
$weekStart = new \DateTime('midnight last sunday');
$monthStart = new \DateTime('midnight first day of this month');
$yearStart = new \DateTime('midnight first day of january this year');


echo $today->format('Y-m-d H:i:s')."\n";
echo $weekStart->format('Y-m-d H:i:s')."\n";
echo $monthStart->format('Y-m-d H:i:s')."\n";
echo $yearStart->format('Y-m-d H:i:s')."\n";

• DateTime value can be set upon construction; there's no need to call DateTime::modify().

• Add midnight to get the time set to 00:00:00.

• first day this year doesn't work in PHP, you need to use first day of january this year instead.

Reference: PHP Documentation of relative date formats.