Is there any fast way to get all subarrays where a key value pair was found in a multidimensional array? I can't say how deep the array will be.
Simple example array:
$arr = array(0 => array(id=>1,name=>"cat 1"),
1 => array(id=>2,name=>"cat 2"),
2 => array(id=>3,name=>"cat 1")
);
When I search for key=name and value="cat 1" the function should return:
array(0 => array(id=>1,name=>"cat 1"),
1 => array(id=>3,name=>"cat 1")
);
I guess the function has to be recursive to get down to the deepest level.
Code:
function search($array, $key, $value)
{
$results = array();
if (is_array($array)) {
if (isset($array[$key]) && $array[$key] == $value) {
$results[] = $array;
}
foreach ($array as $subarray) {
$results = array_merge($results, search($subarray, $key, $value));
}
}
return $results;
}
$arr = array(0 => array(id=>1,name=>"cat 1"),
1 => array(id=>2,name=>"cat 2"),
2 => array(id=>3,name=>"cat 1"));
print_r(search($arr, 'name', 'cat 1'));
Output:
Array
(
[0] => Array
(
[id] => 1
[name] => cat 1
)
[1] => Array
(
[id] => 3
[name] => cat 1
)
)
If efficiency is important you could write it so all the recursive calls store their results in the same temporary $results
array rather than merging arrays together, like so:
function search($array, $key, $value)
{
$results = array();
search_r($array, $key, $value, $results);
return $results;
}
function search_r($array, $key, $value, &$results)
{
if (!is_array($array)) {
return;
}
if (isset($array[$key]) && $array[$key] == $value) {
$results[] = $array;
}
foreach ($array as $subarray) {
search_r($subarray, $key, $value, $results);
}
}
The key there is that search_r
takes its fourth parameter by reference rather than by value; the ampersand &
is crucial.
FYI: If you have an older version of PHP then you have to specify the pass-by-reference part in the call to search_r
rather than in its declaration. That is, the last line becomes search_r($subarray, $key, $value, &$results)
.