Getting Nested Values From Associative Array - php

Question

This is sort of a general implementation question. If I have an arbitrarily deep array, and I do not know before hand what the keys will be, what is the best way to access the values at specific paths of the associative array? For example, given the array:
array(
'great-grandparent' = array(
'grandparent' = array(
'parent' = array(
'child' = 'value';
),
'parent2' = 'value';
),
'grandparent2' = 'value';
)
);
Whats the best way to access the value at $array['great-grandparent']['grandparent']['parent']['child'] keeping in mind that I don't know the keys beforehand. I have used eval to construct the above syntax as a string with variable names and then eval'd the string to get the data. But eval is slow and I was hoping for something faster. Something like $class->getConfigValue('great-grandparent/grandparent/'.$parent.'/child'); that would return 'value'
Example of Eval Code
public function getValue($path, $withAttributes=false) {
$path = explode('/', $path);
$rs = '$r = $this->_data[\'config\']';
foreach ($path as $attr) {
$rs .= '[\'' . $attr . '\']';
}
$rs .= ';';
$r = null;
#eval($rs);
if($withAttributes === false) {
$r = $this->_removeAttributes($r);
}
return $r;
}

Answer 1

I don't know about the potential speed but you don't need to use eval to do a search like that :
$conf = array(
'great-grandparent' => array(
'grandparent' => array(
'parent' => array(
'child' => 'value searched'
),
'parent2' => 'value'
),
'grandparent2' => 'value'
)
);
$path = 'great-grandparent/grandparent/parent/child';
$path = explode('/', $path);
$result = $conf;
while(count($path) > 0) {
$part = array_shift($path);
if (is_array($result) && array_key_exists($part, $result)) {
$result = $result[$part];
} else {
$result = null;
break;
}
}
echo $result;

Answer 2

Here we go, my solution:
$tree = array(
'great-grandparent' => array(
'grandparent' => array(
'parent' => array(
'child' => 'value1'
),
'parent2' => 'value2'
),
'grandparent2' => 'value3'
)
);
$pathParts = explode('/','great-grandparent/grandparent/parent/child');
$pathParts = array_reverse($pathParts);
echo retrieveValueForPath($tree, $pathParts);
function retrieveValueForPath($node, $pathParts) {
foreach($node as $key => $value) {
if(($key == $pathParts[count($pathParts)-1]) && (count($pathParts)==1)) {
return $value;
}
if($key == $pathParts[count($pathParts)-1]) {
array_pop($pathParts);
}
if(is_array($value)) {
$result = retrieveValueForPath($value, $pathParts);
}
}
return $result;
}