help to optimize a function in php - php

Question

i have created a function in php to convert an string like:
[20110911, 20110913, [20110915, 20110918], 20110920, 20110922, 20110924, [20110926, 20110927], 20110929]
to php array like:
Array
(
[0] => 20110911
[1] => 20110913
[2] => Array
(
[0] => 20110915
[1] => 20110918
)
[3] => 20110920
[4] => 20110922
[5] => 20110924
[6] => Array
(
[0] => 20110926
[1] => 20110927
)
[7] => 20110929
[8] => Array
(
[0] => 20111001
[1] => 20111002
)
[9] => 20111004
[10] => Array
(
[0] => 20111006
[1] => 20111007
)
)
The function is:
function dates2Array($d){
if($d!==''){
$d=substr($d, 1, strlen($d)-2);
$d=explode(', ', $d);
$dates=array();
if(!empty($d)){
$j=1;
foreach($d as $k=>$v){
if(substr($v, 0, 1)==='[') $dates[]=array(substr($v, 1, strlen($v)));
elseif(substr($v, strlen($v)-1, strlen($v))===']'){
$dates[$k-$j][1]=substr($v, 0, strlen($v)-1);
$j++;
}
else $dates[]=$v;
}
}
}
return $d!==''?$dates:'';
}
I am not fully happy with my function.
I think it can be more optimized and compressed for speed..
Can it be?

Answer 1

Use JSON (json_decode() and json_encode()) instead
http://sandbox.phpcode.eu/g/b3814/2
result:
Array
(
[0] => 20110911
[1] => 20110913
[2] => Array
(
[0] => 20110915
[1] => 20110918
)
[3] => 20110920
[4] => 20110922
[5] => 20110924
[6] => Array
(
[0] => 20110926
[1] => 20110927
)
[7] => 20110929
)

Answer 2

You can pass your string in {...} and pass it to json_decode(str, true) to get back an array.
>> json_decode("[20110911, 20110913, [20110915, 20110918], 20110920, 20110922, 2
0110924, [20110926, 20110927], 20110929]")
array (
0 => 20110911,
1 => 20110913,
2 =>
array (
0 => 20110915,
1 => 20110918,
),
3 => 20110920,
4 => 20110922,
5 => 20110924,
6 =>
array (
0 => 20110926,
1 => 20110927,
),
7 => 20110929,
)