Fatal error on DateTime::diff on string - php

Question

I ask here well knowing that there is other questions and answers on this and i have been going through them:
Calculate number of hours between 2 dates in PHP
But i still can't find a solution to my problem.
Here is the scenario:
Im using the Google Calendar Api. I have a foreach() loop running, where it graps the dateTime() for the event.
I want to get the differens from the start and end time. My code is as follows:
$neweventDateStr = new DateTime($event->start->dateTime);
$neweventDateEnd = new DateTime($event->end->dateTime);
$diff = $eventDateEnd->diff($neweventDateStr);
However i get the following error on the last line:
Fatal error: Call to a member function diff() on string
I have checked and both variables are recognised as dateTime Objects.
Therefore i can't figure out why is giving me the error as listed above.
Any clue as to why this is?
Note, the code:
$event->start->dateTime
Returns the value of the date and time from the google server as a dateTime RFC 3339 format: source:
https://developers.google.com/google-apps/calendar/v3/reference/events
It returns the values like so:
$event->start->dateTime = 2015-07-06T14:30:00+02:00
$event->se->dateTime = 2015-07-06T15:30:00+02:00
I have tried to:
echo $neweventDateStr;
and i returns the error(as expected) that the variable couldn't be turned into a string since its a dateTime Object format.

Answer 1

The problem is in your code:-
$diff = $eventDateEnd->diff($neweventDateStr);
it should be :-
$diff = $neweventDateEnd->diff($neweventDateStr); // because no where $eventDateEnd is defined.
An example is as follows:-
<?php
$neweventDateStr = new DateTime('2015-04-04 10:10:10');
$neweventDateEnd = new DateTime('2015-04-10 10:10:10');
$diff = $neweventDateEnd->diff($neweventDateStr); // instead of $eventDateEnd i write $neweventDateEnd
print_r($diff);
?>
Output:-https://eval.in/393320