Dynamic array key in while loop - php

Question

I'm trying to get this working:
I have an array that gets "deeper" every loop. I need to add a new array to the deepest "children" key there is.
while($row = mysql_fetch_assoc($res)) {
array_push($json["children"],
array(
"id" => "$x",
"name" => "Start",
"children" => array()
)
);
}
So, in a loop it would be:
array_push($json["children"] ...
array_push($json["children"][0]["children"] ...
array_push($json["children"][0]["children"][0]["children"] ...
... and so on. Any idea on how to get the key-selector dynamic like this?
$selector = "[children][0][children][0][children]";
array_push($json$selector);

Answer 1

$json = array();
$x = $json['children'];
while($row = mysql_fetch_assoc($res)) {
array_push($x,
array(
"id" => "$x",
"name" => "Start",
"children" => array()
)
);
$x = $x[0]['children'];
}
print_r( $json );

Answer 2

Hmmm - maybe better to assign by reference:
$children =& $json["children"];
while($row = mysql_fetch_assoc($res)) {
array_push($children,
array(
"id" => "$x",
"name" => "Start",
"children" => array()
)
);
$children =& $children[0]['children'];
}

Answer 3

$json = array();
$rows = range('a', 'c');
foreach (array_reverse($rows) as $x) {
$json = array('id' => $x, 'name' => 'start', 'children' => array($json));
}
print_r($json);
If you want to read an array via a string path, split the string in indices, and then you can do something like this to get the value
function f($arr, $indices) {
foreach ($indices as $key) {
if (!isset($arr[$key])) {
return null;
}
$arr = $arr[$key];
}
return $arr;
}