无法从字符串中获取日期

I have date in a string as follows:

$rawDate = "08/08/2017 - 21/09/2017";

To separate two dates from each other I used code as:

$dates = explode("-", $rawDate);

Now I want to print dates as Date1 and Date2 as follows:

$date1 = date('Y-m-d', strtotime($dates[0])); 
echo "Date 1: " . $date1;
echo "<br/>";
$date2 =  date('Y-m-d', strtotime($dates[1]));
echo "Date 2: " . $date2;

I want result as
Date 1: 2017-08-08
Date 2: 2017-09-21

But I am getting result as
Date 1: 2017-08-08
Date 2: 2017-01-01

Can anyone help me how this is happening??

Try this..

$rawDate = "08/08/2017 - 21/09/2017";
$dates = explode(" - ", $rawDate);

$date1 = date('Y-m-d', strtotime(str_replace('/','-',$dates[0]))); 
echo "Date 1: " . $date1;
echo "<br/>";
$date2 =  date('Y-m-d', strtotime(str_replace('/','-',$dates[1])));
echo "Date 2: " . $date2;

Life is a lot easier working with dates if you use DateTime objects, because it's easy to specify the format you're receiving the dates

$rawDate = "08/08/2017 - 21/09/2017";

$dates = explode("-", $rawDate);

$date1 = DateTime::createFromFormat('d/m/Y', trim($dates[0])); 
echo "Date 1: " . $date1->format('Y-m-d');
echo PHP_EOL;
$date2 = DateTime::createFromFormat('d/m/Y', trim($dates[1])); 
echo "Date 2: " . $date2->format('Y-m-d');