Sorry for the terrible title, best I could think of at the time! Say I have a 'path' array like so;
array('this', 'is', 'the', 'path')
What would be the most effective method to end up with the array below?
array(
'this' => array(
'is' => array(
'the' => array(
'path' => array()
)
)
)
)
Just iterate over it with something like array_shift or array_pop:
$inarray = array('this', 'is', 'the', 'path',);
$tree = array();
while (count($inarray)) {
$tree = array(array_pop($inarray) => $tree,);
}
Not tested, but that's the basic structure of it. Recursion also fits the task well. Alternatively, if you don't want to modify the initial array:
$inarray = array('this', 'is', 'the', 'path',);
$result = array();
foreach (array_reverse($inarray) as $key)
$result = array($key => $result,);
I use two similar functions to get and set values by their path within an array:
function array_get($arr, $path)
{
if (!$path)
return null;
$segments = is_array($path) ? $path : explode('/', $path);
$cur =& $arr;
foreach ($segments as $segment) {
if (!isset($cur[$segment]))
return null;
$cur = $cur[$segment];
}
return $cur;
}
function array_set(&$arr, $path, $value)
{
if (!$path)
return null;
$segments = is_array($path) ? $path : explode('/', $path);
$cur =& $arr;
foreach ($segments as $segment) {
if (!isset($cur[$segment]))
$cur[$segment] = array();
$cur =& $cur[$segment];
}
$cur = $value;
}
Then you use them like this:
$value = array_get($arr, 'this/is/the/path');
$value = array_get($arr, array('this', 'is', 'the', 'path'));
array_set($arr, 'here/is/another/path', 23);
function buildArrayFromPath( $path ) {
$out = array();
while( $pop = array_pop($path) ) $out = array($pop => $out);
return $out;
}
One recursive solution:
function find_in_array(&$array, &$path, $_i=0) {
// sanity check
if ( !(is_array($array) && is_array($path)) ) return false;
$c = count($path); if ($_i >= $c) return false;
$k = $path[$_i];
if (array_key_exists($k, $array))
return ($_i == $c-1) ? $array[$k] : find_in_array($array[$k], $path, $_i+1);
else
return false;
}
Parameter $_i is for internal use and should not be set when calling the function.
not really elegant. but it works
$start = array('this', 'is', 'the', 'path')
$result[ $start[0] ][ $start[1] ][ $start[2] ][ $start[3] ] = array ();
