In the 2nd part of Example 2, using "else if" instead of several "if" statements to check the same value would result in fewer comparisons having to be done since the way it's written now the second comparison will always run even if the first one was true. It would be even better to use a switch statement if you're comparing the same variable in each case.
Complete with extra syntax and forgetting your own tips from one example to the next:
> return ($string === "");
parens unnecessary:
return $string === "";
aka
return time() > $end_time;
pretty sure he meant to say
if ($string == '' || $string == null)
> $data = include 'school_data.php';
Oh god, no…
> $data_update = $data + array( 'name' => 'surname', 'size' => 40 );
That's not an array update, since it doesn't update the first array.
> if(!is_array( $options )) $options = (array)$options;
That's absolutely horrible, you've got to know that contrary to what you might expect PHP doesn't convert a sequence of characters (a string) into an array of characters, but essentially does `array($options)` (create a 1-element array with the string). So write that.