How to find entry by object property from an array of objects?

Question

The array looks like:

[0] => stdClass Object
        (
            [ID] => 420
            [name] => Mary
         )

[1] => stdClass Object
        (
            [ID] => 10957
            [name] => Blah
         )
...

And I have an integer variable called $v.

How could I select an array entry that has an object where the ID property has the $v value?

Answer 1

You either iterate the array, searching for the particular record (ok in a one time only search) or build a hashmap using another associative array.

For the former, something like this

$item = null;
foreach($array as $struct) {
    if ($v == $struct->ID) {
        $item = $struct;
        break;
    }
}

See this question and subsequent answers for more information on the latter - Reference PHP array by multiple indexes

Answer 2

$arr = [
  [
    'ID' => 1
  ]
];

echo array_search(1, array_column($arr, 'ID')); // prints 0 (!== false)

Above code echoes the index of the matching element, or false if none.

To get the corresponding element, do something like:

$i = array_search(1, array_column($arr, 'ID'));
$element = ($i !== false ? $arr[$i] : null);

array_column works both on an array of arrays, and on an array of objects.

Answer 3

YurkamTim is right. It needs only a modification:

After function($) you need a pointer to the external variable by "use(&$searchedValue)" and then you can access the external variable. Also you can modify it.

$neededObject = array_filter(
    $arrayOfObjects,
    function ($e) use (&$searchedValue) {
        return $e->id == $searchedValue;
    }
);

Answer 4

I've found more elegant solution here. Adapted to the question it may look like:

$neededObject = array_filter(
    $arrayOfObjects,
    function ($e) use ($searchedValue) {
        return $e->id == $searchedValue;
    }
);

Answer 5

Using array_column to re-index will save time if you need to find multiple times:

$lookup = array_column($arr, NULL, 'id');   // re-index by 'id'

Then you can simply $lookup[$id] at will.

Answer 6

Try

$entry = current(array_filter($array, function($e) use($v){ return $e->ID==$v; }));

working example here

Answer 7

class ArrayUtils
{
    public static function objArraySearch($array, $index, $value)
    {
        foreach($array as $arrayInf) {
            if($arrayInf->{$index} == $value) {
                return $arrayInf;
            }
        }
        return null;
    }
}

Using it the way you wanted would be something like:

ArrayUtils::objArraySearch($array,'ID',$v);

Answer 8

Fixing a small mistake of the @YurkaTim, your solution work for me but adding use:

To use $searchedValue, inside of the function, one solution can be use ($searchedValue) after function parameters function ($e) HERE.

the array_filter function only return on $neededObject the if the condition on return is true

If $searchedValue is a string or integer:

$searchedValue = 123456; // Value to search.
$neededObject = array_filter(
    $arrayOfObjects,
    function ($e) use ($searchedValue) {
        return $e->id == $searchedValue;
    }
);
var_dump($neededObject); // To see the output

If $searchedValue is array where we need check with a list:

$searchedValue = array( 1, 5 ); // Value to search.
$neededObject  = array_filter(
    $arrayOfObjects,
    function ( $e ) use ( $searchedValue ) {
        return in_array( $e->term_id, $searchedValue );
    }
);
var_dump($neededObject); // To see the output

Answer 9

I sometimes like using the array_reduce() function to carry out the search. It's similar to array_filter() but does not affect the searched array, allowing you to carry out multiple searches on the same array of objects.

$haystack = array($obj1, $obj2, ...); //some array of objects
$needle = 'looking for me?'; //the value of the object's property we want to find

//carry out the search
$search_results_array = array_reduce(
  $haystack,

  function($result_array, $current_item) use ($needle){
      //Found the an object that meets criteria? Add it to the the result array 
      if ($current_item->someProperty == $needle){
          $result_array[] = $current_item;
      }
      return $result_array;
  },
  array() //initially the array is empty (i.e.: item not found)
);

//report whether objects found
if (count($search_results_array) > 0){
  echo "found object(s): ";
  print_r($search_results_array[0]); //sample object found
} else {
  echo "did not find object(s): ";
}

Answer 10

Way to instantly get first value:

$neededObject = array_reduce(
    $arrayOfObjects,
    function ($result, $item) use ($searchedValue) {
        return $item->id == $searchedValue ? $item : $result;
    }
);

Answer 11

I did this with some sort of Java keymap. If you do that, you do not need to loop over your objects array every time.

<?php

//This is your array with objects
$object1 = (object) array('id'=>123,'name'=>'Henk','age'=>65);
$object2 = (object) array('id'=>273,'name'=>'Koos','age'=>25);
$object3 = (object) array('id'=>685,'name'=>'Bram','age'=>75);
$firstArray = Array($object1,$object2);
var_dump($firstArray);

//create a new array
$secondArray = Array();
//loop over all objects
foreach($firstArray as $value){
    //fill second        key          value
    $secondArray[$value->id] = $value->name;
}

var_dump($secondArray);

echo $secondArray['123'];

output:

array (size=2)
  0 => 
    object(stdClass)[1]
      public 'id' => int 123
      public 'name' => string 'Henk' (length=4)
      public 'age' => int 65
  1 => 
    object(stdClass)[2]
      public 'id' => int 273
      public 'name' => string 'Koos' (length=4)
      public 'age' => int 25
array (size=2)
  123 => string 'Henk' (length=4)
  273 => string 'Koos' (length=4)
Henk

Answer 12

I solved this problem by keying the array with the ID. It's simpler and possibly faster for this scenario where the ID is what you're looking for.

[420] => stdClass Object
        (
            [name] => Mary
         )

[10957] => stdClass Object
        (
            [name] => Blah
         )
...

Now I can directly address the array:

$array[$v]->name = ...

Or, if I want to verify the existence of an ID:

if (array_key_exists($v, $array)) { ...

Answer 13

I posted what I use to solve this very issue efficiently here using a quick Binary Search Algorithm: https://stackoverflow.com/a/52786742/1678210

I didn't want to copy the same answer. Someone else had asked it slightly differently but the answer is the same.