Convert DateTime to String PHP

before researched a lot of Website on how can i convert PHP DateTime object to String. I always see "String to DateTime" and not "DateTime to String"
PHP DateTime can be echoed, but what i want to process my DateTime with PHP string functions.
Now my question is how can I make PHP dateTime Object to a string starting from this kind of codes
<?php
$dts = new DateTime(); //this returns the current date time
echo strlen($dts);
?>

Solution:

You can use the format method of the DateTime class:
$date = new DateTime('2000-01-01');
$result = $date->format('Y-m-d H:i:s');
If format fails for some reason, it will return FALSE. In some applications, it might make sense to handle the failing case:
if ($result) {
  echo $result;
} else { // format failed
  echo "Unknown Time";
}