PHP按日期和年份分开数据

I have data like this

Title - August 2013
Title2 - August 2013
Title3 - October 2013

What I am trying to do is write up to separate these by date and return a link per a month and year, my expected results are:

August 2013
October 2013

I started writing this code:

<?php 

$data = array("Title - August 2013", "Title2 - August 2013", "Title3 - October 2013");

foreach($data as $index){

    $date = explode(" - ", $index);

    echo $date[1];

}

?>

I just don't know how I would go about the rest to only display a date once. I suppose I could create an array in the foreach and check if the date is inside the array.

Any ideas?

Well, yea... Put dates to array and then remove duplications:

$data = array('Title - August 2013', 'Title2 - August 2013', 'Title3 - October 2013');

$dates = array();
foreach($data as $index) {
    $date = explode(' - ', $index);
    $dates[] = $date[1];
}

$dates = array_unique($dates);

var_dump($dates);

Result will be:

array (size=2)
  0 => string 'August 2013' (length=11)
  2 => string 'October 2013' (length=12)