I have a unique case where I have an array like so:
$a = array('a' => array('b' => array('c' => 'woohoo!')));
I want to access values of the array in a manner like this:
some_function($a, array('a')) which would return the array for position a
some_function($a, array('a', 'b', 'c')) which would return the word 'woohoo'
So basically, it drills down in the array using the passed in variables in the second param and checks for the existence of that key in the result. Any ideas on some native php functions that can help do this? I'm assuming it'll need to make use of recursion. Any thoughts would be really appreciated.
Thanks.
This is untested but you shouldn't need recursion to handle this case:
function getValueByKey($array, $key) {
foreach ($key as $val) {
if (!empty($array[$val])) {
$array = $array[$val];
} else return false;
}
return $array;
}
You could try with RecursiveArrayIterator
Here is an example on how to use it.
Here’s a recursive implementation:
function some_function($array, $path) {
if (!count($path)) {
return;
}
$key = array_shift($path);
if (!array_key_exists($key, $array)) {
return;
}
if (count($path) > 1) {
return some_function($array[$key], $path);
} else {
return $array[$key];
}
}
And an iterative implementation:
function some_function($array, $path) {
if (!count($path)) {
return;
}
$tmp = &$array;
foreach ($path as $key) {
if (!array_key_exists($key, $tmp)) {
return;
}
$tmp = &$tmp[$key];
}
return $tmp;
}
These functions will return null if the path is not valid.
$a['a'] returns the array at position a.
$a['a']['b']['c'] returns woohoo.
Won't this do?
Related
My array looks like this:
array( '0|500|0.50', '501|1000|0.75' );
I am trying to run a search to get the KEY which has the searched value.
I made this function to search:
function cu_array_search($str,$array){
foreach($array as $key => $value) {
if(strstr($str,$value)) {
return true;
} else {
return false;
}
}
}
and using it like this when checking:
if (cu_array_search(500,$array) {
but it never return true, despite that 500 exists in first key in array .
How to resolve this?
Thanks
strpos will make you function return true even that's 0.5001 but not 500.
You should explode the value by |, then check whether the number in the array.
function cu_array_search($num, $array){
return count(array_filter($array, function ($var) use ($num) {
return in_array($num, explode('|', $var));
})) > 0;
}
The haystack is the first argument, not the second:
if(strstr($value,$str)) {
Additionally, strpos is faster at this, so you should use:
function cu_array_search($str,$array){
foreach($array as $key => $value) {
if(strpos($value,$str) !== false) {
return $key;
} else {
return false;
}
}
}
First, strstr parameters are wrong
Second, return false should be at the end of the loop.
Third, If you need KEY then You need to use return $key instead of return true
function cu_array_search($str,$array){
foreach($array as $key => $value) {
if(strstr($value, $str)) {
return $key;
}
}
return false;
}
This works fine
<?php
function cu_array_search($str, $array) {
foreach($array as $key => $value) {
$temp_array=explode('|', $value);
if (in_array($str, $temp_array))
return true;
}
return false;
}
$array = array( '0|500|0.50', '501|1000|0.75' );
if (cu_array_search(500, $array))
echo "success";
else
echo "failed" ;
?>
array_walk_recursive($arr, function(&$val, $key){
if($val == 'smth'){
unset($val); // <- not working, unset($key) doesn't either
$var = null; // <- setting it to null works
}
});
print_r($arr);
I don't want it to be null, I want the element out of the array completely. Is this even possible with array_walk_recursive?
You can't use array_walk_recursive here but you can write your own function. It's easy:
function array_unset_recursive(&$array, $remove) {
$remove = (array)$remove;
foreach ($array as $key => &$value) {
if (in_array($value, $remove)) {
unset($array[$key]);
} elseif (is_array($value)) {
array_unset_recursive($value, $remove);
}
}
}
And usage:
array_unset_recursive($arr, 'smth');
or remove several values:
array_unset_recursive($arr, ['smth', 51]);
unset($val) will only remove the local $val variable.
There is no (sane) way how you can remove an element from the array inside array_walk_recursive. You probably will have to write a custom recursive function to do so.
The answer of #dfsq is correct but this function doesn't remove empty array. So you can end up with Tree of empty array, which is not what is expected in most cases.
I used this modified function instead:
public function array_unset_recursive(&$array, $remove) {
foreach ($array as $key => &$value) {
if (is_array($value)) {
$arraySize = $this->array_unset_recursive($value, $remove);
if (!$arraySize) {
unset($array[$key]);
}
} else if (in_array($key, $remove, true)){
unset($array[$key]);
}
}
return count($array);
}
private function find($needle, $haystack) {
foreach ($haystack as $name => $file) {
if ($needle == $name) {
return $file;
} else if(is_array($file)) { //is folder
return $this->find($needle, $file); //file is the new haystack
}
}
return "did not find";
}
Hey, this method searches for a specific key in an associative array and returns the value associated with it. There's some problem with the recursion. Any clue?
Maybe it's overkill, but it's funny to use RecursiveIterators :)
UPDATE: Maybe it was overkill with old versions of PHP, but with >=5.6 (specially with 7.0) I would totally use this without doubt.
function recursiveFind(array $haystack, $needle)
{
$iterator = new RecursiveArrayIterator($haystack);
$recursive = new RecursiveIteratorIterator(
$iterator,
RecursiveIteratorIterator::SELF_FIRST
);
foreach ($recursive as $key => $value) {
if ($key === $needle) {
return $value;
}
}
}
UPDATE: Also, as of PHP 5.6, with generators you can easily iterate over all elements which pass the filter, not only the first one:
function recursiveFind(array $haystack, $needle)
{
$iterator = new RecursiveArrayIterator($haystack);
$recursive = new RecursiveIteratorIterator(
$iterator,
RecursiveIteratorIterator::SELF_FIRST
);
foreach ($recursive as $key => $value) {
if ($key === $needle) {
yield $value;
}
}
}
// Usage
foreach (recursiveFind($haystack, $needle) as $value) {
// Use `$value` here
}
function array_search_key( $needle_key, $array ) {
foreach($array AS $key=>$value){
if($key == $needle_key) return $value;
if(is_array($value)){
if( ($result = array_search_key($needle_key,$value)) !== false)
return $result;
}
}
return false;
}
this will work !
you need to stop the recursive deep search, by return false and then check it in the function.
you can find more examples of functions (like using RecursiveArrayIterator and more) in this link :
http://php.net/manual/en/function.array-search.php
The answer provided by xPheRe was extremely helpful, but didn't quite solve the problem in my implementation. There are multiple nested associative arrays in our data structure, and there may be multiple occurrences of any given key.
In order to suit our purposes, I needed to implement a holder array that was updated while traversing the entire structure, instead of returning on the first match. The real work was provided by another poster, but I wanted to say thanks and share the final step that I had to cover.
public function recursiveFind(array $array, $needle)
{
$iterator = new RecursiveArrayIterator($array);
$recursive = new RecursiveIteratorIterator($iterator, RecursiveIteratorIterator::SELF_FIRST);
$aHitList = array();
foreach ($recursive as $key => $value) {
if ($key === $needle) {
array_push($aHitList, $value);
}
}
return $aHitList;
}
try this:
array_walk_recursive(
$arrayToFindKey,
function($value, $key, $matchingKey){
return (strcasecmp($key, $matchingKey) == 0)? true : false;
}
, 'matchingKeyValue'
);
The best solution above misses the case if the key is repeated and only returns the first value, here I get all the values in an array instead:
function recursiveFind(array $array, $needle) {
$iterator = new RecursiveArrayIterator($array);
$recursive = new RecursiveIteratorIterator($iterator, RecursiveIteratorIterator::SELF_FIRST);
$return = [];
foreach ($recursive as $key => $value) {
if ($key === $needle) {
$return[] = $value;
}
}
return $return;
}
I just been through a similar issue and here's what worked for me:
function searchArrayByKey($haystack, $needle, $i = 0) {
$result = array();
foreach($haystack as $key => $value) {
if (is_array($value)) {
$nextKey = searchArrayByKey($value, $needle);
if ($nextKey) {
return $nextKey;
}
}
if (is_array($value) && array_key_exists($needle, $value)) {
$result[$i++] = $value[$needle];
}
}
if (empty($result)) {
return false;
} else {
return $result;
}
}
This is going to return an array containing the value of all the matching keys it found in the multidimensional array. I tested this with arrays dinamically generated by an e-mail API. In the case of multiple matches, you just need to create a simple foreach loop to sort the array however you want.
I noticed the main mistake I was making was using if-ifelse conditions when I should be using if-if conditions. Any questions or criticism are very welcome, cheers!
I recently came across the same issue, when dealing with Yii2 query object.
The reason your function didn't work is that the return action doesn't work here. Just pass a reference parameter to store the value, and do whatever you want afterwards.
As you can see, this is a simple PHP function doesn't rely on any library. So I think its worth to mention with all the answer listed above.
function array_search_by_key_recursive($needle, array $haystack, &$return)
{
foreach ($haystack as $k => $v) {
if (is_array($v)) {
array_search_by_key_recursive($needle, $v, $return);
} else {
if($k === $needle){
$return = $v;
}
}
}
}
array_search_by_key_recursive($needle, array $haystack, $return);
print_r($return);
Is it possible in PHP to extract values from an array with a particular key path and return an array of those values? I'll explain with an example:
$user =
array (
array(
'id' => 1,
'email' =>'asd#example.com',
'project' => array ('project_id' => 222, 'project_name' => 'design')
),
array(
'id' => 2,
'email' =>'asd2#example.com',
'project' => array ('project_id' => 333, 'project_name' => 'design')
)
);
/** I have to write a function something like: */
$projectIds = extractValuesWithKey($user, array('project', 'project_id'));
print_r($projectIds);
Output:
Array(
[0] => 222,
[1] => 333
)
I would have gone for a different approach (not that there's anything wrong with the array-function-based answers) by using a recursive iterator to flatten the array which makes the key-path comparison fairly simple.
function extractValuesWithKey($array, $keys) {
$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($array));
$keys_count = count($keys);
// No point going deeper than we have to!
$iterator->setMaxDepth($keys_count);
$result = array();
foreach ($iterator as $value) {
// Skip any level that can never match our keys
if ($iterator->getDepth() !== $keys_count) {
continue;
}
// Build key path to current item for comparison
$key_path = array();
for ($depth = 1; $depth <= $keys_count; $depth++) {
$key_path[] = $iterator->getSubIterator($depth)->key();
}
// If key paths match, add to results
if ($key_path === $keys) {
$result[] = $value;
}
}
return $result;
}
To make the whole thing more useful, you could even wrap the code into a custom FilterIterator rather than a basic function, but I guess that's probably a different question entirely.
Well, that's easier than you think.
function extractValuesWithKey($array, $parts) {
$return = array();
$rawParts = $parts;
foreach ($array as $value) {
$tmp = $value;
$found = true;
foreach ($parts as $key) {
if (!is_array($tmp) || !isset($tmp[$key])) {
$found = false;
continue;
} else {
$tmp = $tmp[$key];
}
}
if ($found) {
$return[] = $tmp;
}
}
return $return;
}
If the 'key path' isn't dynamic, you can do a one-liner with array_map:
$projectIds = array_map(function($arr) { return $arr['project']['project_id']; }, $user);
Alternatively, for dynamic paths:
function extractValuesWithKey($users, $path) {
return array_map(function($array) use ($path) {
array_walk($path, function($key) use (&$array) { $array = $array[$key]; });
return $array;
}, $users);
}
The closures/anonymous functions only work with PHP 5.3+, and I've no idea how this would compare performance-wise to a double foreach loop. Note also that there's no error checking to ensure that the path exists.
I also used a similiar function in one of my projects, maybe you find this useful:
function extractValuesWithKey($data, $path) {
if(!count($path)) return false;
$currentPathKey = $path[0];
if(isset($data[$currentPathKey])) {
$value = $data[$currentPathKey];
return is_array($value) ? extractValuesWithKey($value, array_slice($path, 1)) : $value;
}
else {
$tmp = array();
foreach($data as $key => $value) {
if(is_array($value)) $tmp[] = extractValuesWithKey($value, $path);
}
return $tmp;
}
}
I'm working on a program that uses PHP's internal array pointers to iterate along a multidimensional array. I need to get an element from the current row, and I've been doing it like so:
$arr[key($arr)]['item']
However, I'd much prefer to use something like:
current($arr)['item'] // invalid syntax
I'm hoping there's a function out there that I've missed in my scan of the documentation that would enable me to access the element like so:
getvalue(current($arr), 'item')
or
current($arr)->getvalue('item')
Any suggestions?
I very much doubt there is such a function, but it's trivial to write
function getvalue($array, $key)
{
return $array[$key];
}
Edit: As of PHP 5.4, you can index array elements directly from function expressions, current($arr)['item'].
Have you tried using one of the iterator classes yet? There might be something in there that does exactly what you want. If not, you can likely get what you want by extending the ArrayObject class.
This function might be a bit lenghty but I use it all the time, specially in scenarious like:
if (array_key_exists('user', $_SESSION) === true)
{
if (array_key_exists('level', $_SESSION['user']) === true)
{
$value = $_SESSION['user']['level'];
}
else
{
$value = 'DEFAULT VALUE IF NOT EXISTS';
}
}
else
{
$value = 'DEFAULT VALUE IF NOT EXISTS';
}
Turns to this:
Value($_SESSION, array('user', 'level'), 'DEFAULT VALUE IF NOT EXISTS');
Here is the function:
function Value($array, $key = 0, $default = false)
{
if (is_array($array) === true)
{
if (is_array($key) === true)
{
foreach ($key as $value)
{
if (array_key_exists($value, $array) === true)
{
$array = $array[$value];
}
else
{
return $default;
}
}
return $array;
}
else if (array_key_exists($key, $array) === true)
{
return $array[$key];
}
}
return $default;
}
PS: You can also use unidimensional arrays, like this:
Value($_SERVER, 'REQUEST_METHOD', 'DEFAULT VALUE IF NOT EXISTS');
If this does not work, how is your multidimensional array composed? A var_dump() might help.
$subkey = 'B';
$arr = array(
$subkey => array(
'AB' => 'A1',
'AC' => 'A2'
)
);
echo current($arr[$subkey]);
next($arr[$subkey]);
echo current($arr[$subkey]);
I often use
foreach ($arr as $key=>$val) {
$val['item'] /*$val is the value of the array*/
$key /*$key is the key used */
}
instead of
next($arr)/current($arr)