What is the easiest way to map array of objects to key-value array of objects, where key is some property of an object?
For example:
class Cartoon
{
public $title;
public function __construct($title)
{
$this->title = $title;
}
}
$cartoons = array(new Cartoon('Tom and Jerry'), new Cartoon('Cheburashka'));
$mappedCartoons = array();
foreach ($cartoons as $cartoon)
{
$mappedCartoons[$cartoon->title] = $cartoon;
}
print_r ($mappedCartoons);
PS. I wonder if iteration and the extra variable $mappedCartoons can be disposed of?
You could use array_reduce to achive your goal.
<?php
$cartoons = array_reduce($cartoons, function($result, $cartoon) {
$result[$cartoon->title] = $cartoon;
return $result;
}, array());
?>
the idea is not mine, found here: http://www.danielauener.com/howto-use-array_map-functionality-on-an-associative-array-changing-keys-and-values/
If you must use basic arrays you can simply type out the keys when creating them:
$cartoons = array(
'Tom and Jerry' => new Cartoon('Tom and Jerry'),
'Cheburashka' => new Cartoon('Cheburashka'),
);
Alternatively you can create container object that implements various array/iteration related interfaces and can be used as a regular array:
class CartoonArray extends ArrayObject {
public function __construct($input, $flags = 0, $iterator_class = "ArrayIterator") {
parent::__construct(array(), $flags, $iterator_class);
// since the original ArrayObject implemented in C and they don't it won't pick up our overriden ossetSet we have to type it out here explicitly
foreach ($input as $value) {
$this->offsetSet(null, $value);
}
}
public function offsetSet($index, $value) {
parent::offsetSet($value->title, $value);
}
}
$cartoons = new CartoonArray(array(new Cartoon('Tom and Jerry'), new Cartoon('Cheburashka')));
$cartoons[] = new Cartoon('Sesame street');
print $cartoons['Tom and Jerry']->title;
unset($cartoons['Tom and Jerry']);
foreach ($cartoons as $k => $v) {
print $k."\n";
}
I can't think of a way that doesn't involve iterating. I can think of a way of not needing an additional variable though:
$cartoons = array(new Cartoon('Tom and Jerry'), new Cartoon('Cheburashka'));
foreach( $cartoons as $key => $cartoon )
{
$cartoons[ $cartoon->title ] = $cartoon;
unset( $cartoons[ $key ] );
}
var_dump( $cartoons );
However, the documentation of foreach notes:
As foreach relies on the internal array pointer changing it within the loop may lead to unexpected behavior.
I'm not entirely sure that this applies to my example as well. Maybe someone else can chime in here.
To be safe, perhaps this alternative is more appropriate, as it initiates $len with the initial length of $cartoons, before iteration:
$cartoons = array(new Cartoon('Tom and Jerry'), new Cartoon('Cheburashka'));
for( $i = 0, $len = count( $cartoons ); $i < $len; $i++ )
{
$cartoon = $cartoons[ $i ];
$cartoons[ $cartoon->title ] = $cartoon;
unset( $cartoons[ $i ] );
}
var_dump( $cartoons );
This example assumes the initial $cartoons has 'proper' sequentially numbered keys, starting at 0, though.
Related
In PHP we can do things like these:
Class Example {
...
}
$example = 'Example';
$object = new $example();
Or the use of variable variables:
$hour = 18;
$greets = array('Good morning','Good afternoon','Good evening');
$values = array(13,21,23);//people is sleeping at 23PM, so they don't greet.
$n = count($values);
$greet = 'greets';
for($i=0;$i<$n;$i++){
if($hour < $values[$i]){
echo 'hello, '.${$greet}[$i];
break;
}
}
And others..
I wonder if it would be possible to access directly to a specific index of a multidimensional array in a similar way. Something like:
$array = array(...); //multidimensional array.
$position = '[0][4][3]';
print_r($array$position);
Thanks in advance.
UPDATE
I'm so sorry because I finished my question in a wrong way.
I need to set the multimesional array and add a value. i.e:
$array$position = $data;
You could implement it yourself with a custom function:
function getValueFromMultiDimensionalArray( array $array, string $key )
{
$keys = explode('][', $key);
$value = $array;
foreach ($keys as $theKey) {
// remove the opening or closing bracket if present
$theKey = str_replace([ '[', ']' ], '', $theKey);
if (!isset($value[$theKey])) {
return null;
}
$value = $value[$theKey];
}
return $value;
}
You can define path as dot separated , check the following solution
function getValueByKey($a,$p){
$c = $a;
foreach(explode('.',$p) as $v){
if(!array_key_exists($v, $c)) return null;
$c = $c[$v];
}
return $c;
}
You can use this function as
$path = '1.2.3.0';
$indexValue = getValueByKey($array, $path);
Nope, this is not possible.
The only thing you can do is to implement ArrayAccess interface, which allows to access instances with [] operator. But you will have to define the logic yourself.
class MyClass implements ArrayAccess
{
...
}
$x = new MyClass([0=>[4=>[3=>'hello world']]]);
$position = '[0][4][3]';
echo $x[$position]; //hello world
Imagine you have a deep array like this:
<?php
$array = ['hello' => ['deep' => 'treasure']];
Then you had an array of the keys to access the string 'treasure'
['hello', 'deep'];
How do you delete the string treasure if you did not know the depth of the array till run time
Edit:
My apologises I've definitely not provided enough information for what I'm looking to achieve
Here is some code I've come up with which does what I need but uses unsafe eval (keep in mind the target destination could be an array so array_walk_recursive won't work)
function iterator_keys($iterator, $outer_data) {
$keys = array();
for ($i = 0; $i < $iterator->getDepth() + 1; $i++) {
$sub_iterator = $iterator->getSubIterator($i);
$keys[$i] = ($i == 0 && is_object($outer_data)
|| $i > 0 && is_object($last_iterator->current())) ?
'->{"' . $sub_iterator->key() . '"}' :
'["' . $sub_iterator->key() . '"]';
$last_iterator = $sub_iterator;
}
return $keys;
}
function recursive_filter($data, callable $selector_function, $iterator = NULL) {
$iterator = $iterator ?? new RecursiveIteratorIterator(
new RecursiveArrayIterator($data),
RecursiveIteratorIterator::CHILD_FIRST
);
foreach ($iterator as $key => $value) {
if ($selector_function($value, $key, $iterator)) {
eval('unset($data' . implode('', iterator_keys($iterator, $data)) . ');');
}
}
return $data;
}
The intention is to have a deep data structure a function that evalutes each node and if it matches a condition then remove it from the data structure in place, if this can be done without eval that would be amazing but so far I think PHP can't programmatically delete something that is more than one level deep
Hello I think what you want is somethings like this
<?php
$array = ['hello' => ['deep' => ['deep1' => 'treasure']]];
$keys = ["hello", "deep", "deep1"];
function remove_recursive(&$array, $keys, $level = 0)
{
if ($level >= count($keys)) {
return $array;
}
if (isset($array[$keys[$level]]) && $level == count($keys) - 1) {
unset($array[$keys[$level]]);
} elseif (isset($array[$keys[$level]])) {
$array[$keys[$level]] = remove_recursive($array[$keys[$level]], $keys, $level + 1);
}
return $array;
}
var_dump(remove_recursive($array, $keys));
Well you can try this really quick and dirty way that uses eval to achieve your goal:
$array = ['hello' => ['deep' => 'treasure']];
$keys = ['hello', 'deep'];
$expression = 'unset($array[\'' . implode('\'][\'', $keys) . '\']);';
eval($expression);
But maybe you can tell us more about your development and we can help you reorganize it somehow to avoid this problem at all.
This will set the target array element to null. Optionally you could use '':
$array = ['hello' => ['deep' => 'treasure']];
$path = ['hello', 'deep'];
$temp = &$array;
foreach($path as $key) {
$temp =& $temp[$key];
}
$temp = null;
print_r($array);
Yields:
Array
(
[hello] => Array
(
[deep] =>
)
)
I'm having an array_reduce function which I am willing to exit when specific criteria is met.
$result = array_reduce($input, function($carrier, $item) {
// do the $carrier stuff
if (/* god was one of us */) {
break; //some break analogue
}
return $carrier;
});
How do I achieve this? Or should I use foreach instead?
array_reduce is used to write functional-style code which always iterates over the full array. You can either rewrite to use a regular foreach loop to implement short circuiting logic, or you can simply return the current $carrier unmodified. This will still iterate over your full array, but it will not alter the result (as you said, this is more alike to continue)
Firstly, let me say that array_reduce is probably one of my favorite functions - I am famous (well, in a very small circle) for taking 40 lines of clearly written code and replacing them with four harder-to-follow 10 line array_reduce calls to do the same thing!
Sadly, PHP array functions seem bound to want to complete their task. This, combined with the inability to make a recursive unnamed function, makes this common situation difficult to deal with. Not wanting to put a lot of ugly for loops in my code, I tend to bury them in another function (see reduce below) as did an earlier poster.
It's worth pointing out that this is in no way as efficient as using array functions, and, in most circumstances, it's better just to let the array reduce function use a "done" flag to spin quickly through the unneeded values. At any rate, this is something reasonably array_reduce like (the evaluation function using a null return to indicate its finished). The goal is to add up the numbers in the array until you get to a 4.
<?php
$init = 0;
$arr = [1,2,3,4,5,6,7,8,9,0];
$func = function($c, $it) {
if ($it == 4) return null;
return $c + $it;
};
function reduce($arr, $f, $init) {
for ($c = $init; count($arr); ) {
$newc = $f($c, array_shift($arr));
if (!isset($newc)) break;
$c = $newc;
}
return $c;
}
echo reduce($arr, $func, $init) . "\n"; // 6
According to a similar answer.
Break array_walk from anonymous function
The best and the worst way to complete this is Exception.
Not recommend this way, but this way is the solution to your question:
try {
$result = array_reduce( $input, function ( $carrier, $item ) {
// do the $carrier stuff
$condition = true;
if ( $condition ) {
throw new Exception;
}
return $carrier;
} );
} catch ( Exception $exception ) {
echo 'Break';
}
The way I would solve the problem
I would create a global function or write PHP extension and add a function
There is a good answer about writing PHP extension:
How to make a PHP extension
array_reduce_2();
But there is a problem with breaking implementation.
Need to detect which condition to out of function.
Below implementation, array_reduce_2 checks if a callback returned.
If so - breaking out of execution.
This way allows checking if execution has broken by checking return type of value.
array_reduce_2 implementation
According to #wordragon notice, implemented the ability to pass an associative array as param too.
function array_reduce_2( $array, $callback, $initial = null ) {
$len = count( $array );
$index = 0;
if ( $len == 0 && count( func_get_args() ) == 1 ) {
return null;
}
$values = array_values( $array );
$result = $initial ?? $values[ $index ++ ];
foreach ( $values as $value ) {
$result = $callback( $result, $value );
if ( ! is_callable( $result ) ) {
continue;
}
// break;
return $result;
}
return $result;
}
I've used the idea from JS implementation and rewrite for PHP accordingly
https://gist.github.com/keeto/229931
Detecting if the break occured
$input = [ 'test', 'array', 'god was one of us' ];
$result = array_reduce_2( $input, function ( $carrier, $item ) {
// do the $carrier stuff
if ( $item === 'god was one of us' ) {
return function () {
return 'god was one of us';
};
}
return $carrier;
} );
$is_break = is_callable( $result );
if ( $is_break ) {
echo $result();
exit;
}
Important to note!
This array_reduce_2 implementation works properly only if you don't need to return the normal value as a callback.
I suggest using foreach loops instead. The reasons to not use array_reduce are:
Sound reasons:
It is not statically type-checked. So code inspections do not show type errors if there are any in the input or callback arguments.
It returns mixed, so inspections do not show errors if you misuse the result, or they may show false positive if you use it properly.
You cannot break.
Opinionated reasons:
It is harder on the eye. Having a $result and adding to it in a loop (or whatever you do) is way easier to read than grasping that something is returned and then passed as a $carry accumulator in the next call.
It makes me lazy to extract functions properly. If I extract one operation to a callback, I then may find the code short enough to not extract the whole array operation to a function which should really be done in the first place.
If you use a condition to break, there is a good chance you may one day need other arguments to that callback function. With the callback signature being fixed, you would have to pass arguments with use keyword which really much harder to read than a non-callback.
breakable_array_reduce()
function breakable_array_reduce(array $array, callable $callback, $initial = null) {
$result = $initial;
foreach ($array as $value) {
$ret = $callback($result, $value);
if (false === $ret) {
return $result;
} else {
$result = $ret;
}
}
return $result;
}
Usage
// array of 10 values
$arr = [
1,
1,
1,
1,
1,
1,
1,
1,
1,
1
];
// callback function which stops once value >= 5
$sum_until_five = function($initial, $value) {
if ($initial >= 5) {
return false;
} else {
return $initial + $value;
}
};
// calculate sum of $arr using $sum_until_five()
$sum = breakable_array_reduce($arr, $sum_until_five);
// output: 5
echo $sum;
Explanation
breakable_array_reduce() will work just like array_reduce() unless/until callback $callback returns bool(false)
Alternate implementation using array keys:
breakable_array_reduce_keyed()
function breakable_array_reduce_keyed(array $array, callable $callback, $initial = null) {
$result = $initial;
foreach ($array as $key => $value) {
$ret = $callback($result, $value, $key);
if (false === $ret) {
return $result;
} else {
$result = $ret;
}
}
return $result;
}
Usage
// array of values
$arr = [
'foo' => 1,
'bar' => 1,
'baz' => 1
];
// callback function which stops when $key === 'baz'
$sum_until_baz = function($initial, $value, $key) {
if ('baz' === $key) {
return false;
} else {
return $initial + $value;
}
};
// calculate sum of $arr using $sum_until_baz()
$sum = breakable_array_reduce($arr, $sum_until_baz);
// output: 2
echo $sum;
P.S. I just wrote and fully tested this locally.
I will have a lot unknown levels of array; I would like to delete the selected ones.
Example:
$data = array(
'level1' => array(
'level2' => array(
'level3' => array(
'level4' => 'the end level at currently example, but not always',
'level4_remain' => 'this data will remain'
),
'remain' => 'this data would not delete in this example too'
)
)
'root' => 'this data would not delete in this example'
);
I have a class called vars; it stores all variables globally that I can fetch at anytime; add at anytime, but now that I'm going to make the delete method, I worry about the multi-level issue:
class vars {
public static $data = array();
public static function get($key){
$key = explode('/', $key);
$v = self::$data;
foreach($key as $k)
{
if(!isset($v[$k]))
{
return null;
}
$v = &$v[$k];
}
return $v;
}
public static function has($key){
.........
}
public static function del($key){
$key = explode('/', $key);
//....Any idea how to do this....//
}
}
and I will use the get method like this:
$blabla = vars::get('level1/level2/level3/level4');
and return correct data, but in the del method, I have no idea what to do:
$deleted = vars::del('level1/level2/level3/level4');
It needs to be finished after deleting the array:
unset($data['level1']['level2']['level3']['level4']);
After doing some research I found this, but this is just for "set" level of array, not automatically set as many level as it can be:
foreach ($data as $k1 => $arr) {
foreach ($arr as $k2 => $arr2) {
foreach ($arr2 as $k3 => $arr3) {
if ($k3 == $key) {
unset($rules[$k1][$k2][$k3]);
}
}
}
}
and I think it can be done like this but is quite ugly:
foreach($data as $k1 => $arr1){
if(is_array($arr1)){
foreach($arr1 as $k2 => $arr2){
//...keep writing the if(is_array()){}else{} and foreach(){} for more level deeper...//
}
}else{
//...the unset should be here...//
}
}
After some research, eval might be harmful, so anyone have any ideas how to do this using any method except eval?
If you don't mind using eval...
public static function del($levels)
{
$lvls = explode('/', $levels);
$count = count($lvls);
$eval = '';
for ($i=0; $i<$count; ++$i) {
// Current Array Key
$key = $lvls[$i];
$eval .= "['$key']";
}
$eval = 'self::data' . $eval;
eval("unset($eval);");
}
However, running untrusted (like User input) through eval can be dangerous.
To avoid eval, you can go the recursive route. The trick is to loop over your indices and pass a subarray reference repeatedly, similar to your get function, just recursively.
public static function del($key){
$key = array_reverse( explode('/', $key) ); // _reverse for _pop later
del_r(self::$data,$key); // start the recursive function
}
private static function del_r(&$array,$keys) { // shouldn't be used from outside
$key = array_pop($keys); // extract next key, this removes it from $keys
if (count($keys)) { // still keys left -> recurse further
del_r($array[$key],$keys); // pass subarray by reference
}
else { // no more keys -> delete the element at the current $key
unset($array[$key]);
}
}
Depending on the number of keys, you can use array_shift() instead of array_pop() and remove the array_reverse().
What would be the fastest, most efficient way to implement a search method that will return an object with a qualifying id?
Sample object array:
$array = [
(object) ['id' => 'one', 'color' => 'white'],
(object) ['id' => 'two', 'color' => 'red'],
(object) ['id' => 'three', 'color' => 'blue']
];
What do I write inside of:
function findObjectById($id){
}
The desired result would return the object at $array[0] if I called:
$obj = findObjectById('one')
Otherwise, it would return false if I passed 'four' as the parameter.
You can iterate that objects:
function findObjectById($id){
$array = array( /* your array of objects */ );
foreach ( $array as $element ) {
if ( $id == $element->id ) {
return $element;
}
}
return false;
}
Edit:
Faster way is to have an array with keys equals to objects' ids (if unique);
Then you can build your function as follow:
function findObjectById($id){
$array = array( /* your array of objects with ids as keys */ );
if ( isset( $array[$id] ) ) {
return $array[$id];
}
return false;
}
It's an old question but for the canonical reference as it was missing in the pure form:
$obj = array_column($array, null, 'id')['one'] ?? false;
The false is per the questions requirement to return false. It represents the non-matching value, e.g. you can make it null for example as an alternative suggestion.
This works transparently since PHP 7.0. In case you (still) have an older version, there are user-space implementations of it that can be used as a drop-in replacement.
However array_column also means to copy a whole array. This might not be wanted.
Instead it could be used to index the array and then map over with array_flip:
$index = array_column($array, 'id');
$map = array_flip($index);
$obj = $array[$map['one'] ?? null] ?? false;
On the index the search problem might still be the same, the map just offers the index in the original array so there is a reference system.
Keep in mind thought that this might not be necessary as PHP has copy-on-write. So there might be less duplication as intentionally thought. So this is to show some options.
Another option is to go through the whole array and unless the object is already found, check for a match. One way to do this is with array_reduce:
$obj = array_reduce($array, static function ($carry, $item) {
return $carry === false && $item->id === 'one' ? $item : $carry;
}, false);
This variant again is with the returning false requirement for no-match.
It is a bit more straight forward with null:
$obj = array_reduce($array, static function ($carry, $item) {
return $carry ?? ($item->id === 'one' ? $item : $carry);
}, null);
And a different no-match requirement can then be added with $obj = ...) ?? false; for example.
Fully exposing to foreach within a function of its own even has the benefit to directly exit on match:
$result = null;
foreach ($array as $object) {
if ($object->id === 'one') {
$result = $object;
break;
}
}
unset($object);
$obj = $result ?? false;
This is effectively the original answer by hsz, which shows how universally it can be applied.
You can use the function array_search of php like this
$key=array_search("one", array_column(json_decode(json_encode($array),TRUE), 'color'));
var_dump($array[$key]);
i: is the index of item in array
1: is the property value looking for
$arr: Array looking inside
'ID': the property key
$i = array_search(1, array_column($arr, 'ID'));
$element = ($i !== false ? $arr[$i] : null);
Well, you would would have to loop through them and check compare the ID's unless your array is sorted (by ID) in which case you can implement a searching algorithm like binary search or something of that sort to make it quicker.
My suggestion would be to first sort the arrays using a sorting algorithm (binary sort, insertion sort or quick sort) if the array is not sorted already. Then you can implement a search algorithm which should improve performance and I think that's as good as it gets.
http://www.algolist.net/Algorithms/Binary_search
This is my absolute favorite algorithm for very quickly finding what I need in a very large array, quickly. It is a Binary Search Algorithm implementation I created and use extensively in my PHP code. It hands-down beats straight-forward iterative search routines. You can vary it a multitude of ways to fit your need, but the basic algorithm remains the same.
To use it (this variation), the array must be sorted, by the index you want to find, in lowest-to-highest order.
function quick_find(&$array, $property, $value_to_find, &$first_index) {
$l = 0;
$r = count($array) - 1;
$m = 0;
while ($l <= $r) {
$m = floor(($l + $r) / 2);
if ($array[$m]->{$property} < $value_to_find) {
$l = $m + 1;
} else if ($array[$m]->{$property} > $value_to_find) {
$r = $m - 1;
} else {
$first_index = $m;
return $array[$m];
}
}
return FALSE;
}
And to test it out:
/* Define a class to put into our array of objects */
class test_object {
public $index;
public $whatever_you_want;
public function __construct( $index_to_assign ) {
$this->index = $index_to_assign;
$this->whatever_you_want = rand(1, 10000000);
}
}
/* Initialize an empty array we will fill with our objects */
$my_array = array();
/* Get a random starting index to simulate data (possibly loaded from a database) */
$my_index = rand(1256, 30000);
/* Say we are needing to locate the record with this index */
$index_to_locate = $my_index + rand(200, 30234);
/*
* Fill "$my_array()" with ONE MILLION objects of type "test_object"
*
* 1,000,000 objects may take a little bit to generate. If you don't
* feel patient, you may lower the number!
*
*/
for ($i = 0; $i < 1000000; $i++) {
$searchable_object = new test_object($my_index); // Create the object
array_push($my_array, $searchable_object); // Add it to the "$my_array" array
$my_index++; /* Increment our unique index */
}
echo "Searching array of ".count($my_array)." objects for index: " . $index_to_locate ."\n\n";
$index_found = -1; // Variable into which the array-index at which our object was found will be placed upon return of the function.
$object = quick_find($my_array, "index", $index_to_locate, $index_found);
if ($object == NULL) {
echo "Index $index_to_locate was not contained in the array.\n";
} else {
echo "Object found at index $index_found!\n";
print_r($object);
}
echo "\n\n";
Now, a few notes:
You MAY use this to find non-unique indexes; the array MUST still be sorted in ascending order. Then, when it finds an element matching your criteria, you must walk the array backwards to find the first element, or forward to find the last. It will add a few "hops" to your search, but it will still most likely be faster than iterating a large array.
For STRING indexes, you can change the arithmetic comparisons (i.e. " > " and " < " ) in quick_find() to PHP's function "strcasecmp()". Just make sure the STRING indexes are sorted the same way (for the example implementation): Alphabetically and Ascending.
And if you want to have a version that can search arrays of objects sorted in EITHER ascending OR decending order:
function quick_find_a(&$array, $property, $value_to_find, &$first_index) {
$l = 0;
$r = count($array) - 1;
$m = 0;
while ($l <= $r) {
$m = floor(($l + $r) / 2);
if ($array[$m]->{$property} < $value_to_find) {
$l = $m + 1;
} else if ($array[$m]->{$property} > $value_to_find) {
$r = $m - 1;
} else {
$first_index = $m;
return $array[$m];
}
}
return FALSE;
}
function quick_find_d(&$array, $property, $value_to_find, &$first_index) {
$l = 0;
$r = count($array) - 1;
$m = 0;
while ($l <= $r) {
$m = floor(($l + $r) / 2);
if ($value_to_find > $array[$m]->{$property}) {
$r = $m - 1;
} else if ($value_to_find < $array[$m]->{$property}) {
$l = $m + 1;
} else {
$first_index = $m;
return $array[$m];
}
}
return FALSE;
}
function quick_find(&$array, $property, $value_to_find, &$first_index) {
if ($array[0]->{$property} < $array[count($array)-1]->{$property}) {
return quick_find_a($array, $property, $value_to_find, $first_index);
} else {
return quick_find_d($array, $property, $value_to_find, $first_index);
}
}
The thing with performance of data structures is not only how to get but mostly how to store my data.
If you are free to design your array, use an associative array:
$array['one']->id = 'one';
$array['one']->color = 'white';
$array['two']->id = 'two';
$array['two']->color = 'red';
$array['three']->id = 'three';
$array['three']->color = 'blue';
Finding is then the most cheap: $one = $array['one];
UPDATE:
If you cannot modify your array constitution, you could create a separate array which maps ids to indexes. Finding an object this way does not cost any time:
$map['one'] = 0;
$map['two'] = 1;
$map['three'] = 2;
...
getObjectById() then first lookups the index of the id within the original array and secondly returns the right object:
$index = $map[$id];
return $array[$index];
Something I like to do in these situations is to create a referential array, thus avoiding having to re-copy the object but having the power to use the reference to it like the object itself.
$array['one']->id = 'one';
$array['one']->color = 'white';
$array['two']->id = 'two';
$array['two']->color = 'red';
$array['three']->id = 'three';
$array['three']->color = 'blue';
Then we can create a simple referential array:
$ref = array();
foreach ( $array as $row )
$ref[$row->id] = &$array[$row->id];
Now we can simply test if an instance exists in the array and even use it like the original object if we wanted:
if ( isset( $ref['one'] ) )
echo $ref['one']->color;
would output:
white
If the id in question did not exist, the isset() would return false, so there's no need to iterate the original object over and over looking for a value...we just use PHP's isset() function and avoid using a separate function altogether.
Please note when using references that you want use the "&" with the original array and not the iterator, so using &$row would not give you what you want.
This is definitely not efficient, O(N). But it looks sexy:
$result = array_reduce($array, function ($found, $obj) use ($id) {
return $obj['id'] == $id ? $obj : $found;
}, null);
addendum:
I see hakre already posted something akin to this.
Here is what I use. Reusable functions that loop through an array of objects. The second one allows you to retrieve a single object directly out of all matches (the first one to match criteria).
function get_objects_where($match, $objects) {
if ($match == '' || !is_array($match)) return array ();
$wanted_objects = array ();
foreach ($objects as $object) {
$wanted = false;
foreach ($match as $k => $v) {
if (is_object($object) && isset($object->$k) && $object->$k == $v) {
$wanted = true;
} else {
$wanted = false;
break;
};
};
if ($wanted) $wanted_objects[] = $object;
};
return $wanted_objects;
};
function get_object_where($match, $objects) {
if ($match == '' || !is_array($match)) return (object) array ();
$wanted_objects = get_objects_where($match, $objects);
return count($wanted_objects) > 0 ? $wanted_objects[0] : (object) array ();
};
The easiest way:
function objectToArray($obj) {
return json_decode(json_encode($obj), true);
}