how to concatenate two array element values in php by special charcter?

i have two arrays given below

Array
(
    [0] => 2013-07-09
    [1] => 2013-07-16
    [2] => 2013-07-23
    [3] => 2013-07-30
)

Array
(
    [0] => 2013-07-16
    [1] => 2013-07-23
    [2] => 2013-07-30
    [3] => 2013-08-06

)

i want to concatenate two array element values by special character.given output below:

Array
(
    [0] => 2013-07-09 : 2013-07-16
    [1] => 2013-07-16 : 2013-07-23
    [2] => 2013-07-23 : 2013-08-30
    [3] => 2013-08-30 : 2013-08-06

)

Answer

Try with array_map like this

$combined = array_map(function($a, $b) { return $a . ' : ' . $b; }, $array1, $array2);