PHP Fastest way to check if a value in the array exists

Question

I have this array:

array [▼
      0 => array:5 [▼
        "id" => 1
        "user_id" => 15
        "parent_campaign_id" => 69464
        "child_campaign_id" => 69464
        "cpm" => "1.00"
      ]
      1 => array:5 [▼
        "id" => 2
        "user_id" => 15
        "parent_campaign_id" => 69464
        "child_campaign_id" => 396331
        "cpm" => "2.00"
      ]
      2 => array:5 [▼
        "id" => 3
        "user_id" => 15
        "parent_campaign_id" => 69464
        "child_campaign_id" => 398032
        "cpm" => "3.00"
      ]
    ]

How can I know if a number 396331 exists in that array and the key should be child_campaign_id.

I tried in_array() but it seems it is not working correctly since the keys of this array is different.

Your help will be greatly appreciated.

Possible duplicate of [PHP: Check if value and key exist in multidimensional array](http://stackoverflow.com/questions/6990855/php-check-if-value-and-key-exist-in-multidimensional-array) — Rajdeep Paul, Dec 01 '16 at 14:23
Good information and benchmarks showing alternate methods here: [Nickology: **Faster array lookup than using `in_array()` (PHP)**](http://nickology.com/2012/07/03/php-faster-array-lookup-than-using-in_array/) — ashleedawg, Jan 13 '19 at 02:29

lonesomeday · Accepted Answer · 2016-12-01T15:20:29.317

8

The simple and clean version uses array_filter.

$filtered = array_filter($original, function($element) {
    return $element['child_campaign_id'] === 396331;
});

if (count($filtered)) {
    // it exists
} else {
    // it doesn't
}

It is, of course, possible to use a variable as the search key if you wish:

$search = 396331; // or whatever
$filtered = array_filter($original, function($element) use ($search) {
    return $element['child_campaign_id'] === $search;
});

Note that the downside of this is that it searches through the entire array, reduces it and then checks to see if there is anything left. A more efficient way, if you have a very large array, would be to loop through and break; when you reach the first matching array element.

edited Dec 01 '16 at 15:20

answered Dec 01 '16 at 14:23

lonesomeday

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What is the `$original` variable there? – PinoyStackOverflower Dec 01 '16 at 14:24
1

@PinoyStackOverflower Your array. – lonesomeday Dec 01 '16 at 14:25
1

@cale_b of course it does support variables: `$fn = function($element) use ($id, $val) {return $element[$id] === $val;}; $filtered = array_filter($original, $fn);` What it does not support is multi-dimentional arrays with D > 2, but it is out of scope. – Alex Blex Dec 01 '16 at 15:02
@cale_b There's a big shiny "edit" button if you want to improve the answer! But I have updated to take your useful points into account. – lonesomeday Dec 01 '16 at 15:21

Dave · Answer 2 · 2016-12-01T14:34:16.153

3

Try this, it will print array index, it will give false result if value is not exist.

$index_array= array_search(396331, array_column($array, "child_campaign_id"));
var_dump($index_array);

DEMO

edited Dec 01 '16 at 14:34

answered Dec 01 '16 at 14:28

Dave

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Note that you can also play with the third parameter of `array_column`, this way you don't have to search the array: `isset(array_column($arr, 'id', 'child_campaign_id')[398032])` (or using `key_exists`) – Casimir et Hippolyte Dec 01 '16 at 15:48

PHP Fastest way to check if a value in the array exists

2 Answers2