arkinEx Codex

function array_trim(&$a){
	foreach( $a as $k => $v )
	{	
		if ( is_array( $a[$k] ) ) array_trim( $a[$k] );
		else $a[$k] = trim( $v );
		if ( empty($a[$k]) ) unset( $a[$k] );
	}
} 
// Useage:
array_trim( $a );