datetime - how do I subtract 24 hour from date time object in PHP -

i have following code:

  $now = date("y-m-d h:m:s");   $date = date("y-m-d h:m:s", strtotime('-24 hours', $now));

however, gives me error:

a non formed numeric value encountered in...

why this?

$date = (new \datetime())->modify('-24 hours');

$date = (new \datetime())->modify('-1 day');

(the latter takes account this comment valid point.)

should work fine here. see http://php.net/datetime

$date instance of datetime, real datetime object.

Live