How to convert 2-demensional array in 1-demednsional array?

Hi,Dear Frnds...............I Hope u are all fine.
I am using the PHP and I want to convert the 2-demensional array
in 1-demensional array.
Here is the code.

$frnd1 = array(
0=> 'arfan',
1=> 'haider',


2=> array(
0=> 'azeem',
1=> 'jeme',
),
3=> array(
0=> 'haider',
1=> 'one'
)
);

Code (markup):

I want to convert this array in simple array.
Suppose it is bulit dynamically Then what I did do?
........Thanks......

 

function toOneDimension($inputArray) {
     $resultArray = array();
     foreach ($inputArray as $element) {
         if (is_array($element)) {
               $resultArray = array_merge($resultArray, toOneDimension($resultArray));
         } else {
               $resultArray[] = $element;
         }
     }
     return $resultArray;
}

PHP:

This code should work, haven't tested myself.