I am trying to make a string from an array.The array structure looks like this
[n3] => Array (  => 2011-01-19  => 2011-01-12 )
Now if n3 or n3 is null i mean if any one value is absent then the string should look like
$str = '2011-01-19/2011-01-12' //any one value
if both values are present then
$str >= '2011-01-19' and $str <= '2011-01-12'