Difference between implode and explode functions

implode

implode acts on an array, and returns a string:
$array = ("Oasis", "Coldplay", "Foo Fighters");
$string = implode(", ", $array);
echo $string;
The above code outputs:
Oasis, Coldplay, Foo Fighters

explode

explode acts on a string, and returns an array:
$string = "Oasis, Coldplay, Foo Fighters";
$array = explode(", ", $string);
echo $array[0];
The above code outputs:
Oasis