How can I remove a key and its value from an associative array?

Question

Given an associative array:

array("key1" => "value1", "key2" => "value2", ...)

How would I go about removing a certain key-value pair, given the key?

score 433 · Accepted Answer · edited Aug 16 '22 at 00:04

433

You can use unset:

unset($array['key-here']);

Example:

$array = array("key1" => "value1", "key2" => "value2");
print_r($array);

unset($array['key1']);
print_r($array);

unset($array['key2']);
print_r($array);

Output:

Array
(
    [key1] => value1
    [key2] => value2
)
Array
(
    [key2] => value2
)
Array
(
)

edited Aug 16 '22 at 00:04

Pang

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answered Jun 16 '10 at 13:15

Sarfraz

377,238
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533
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27

+1: Thanks for the help. PHP newb here, but it's worth noting that if you are trying to perform these edits inside of a `foreach` loop, then you need to prepend an ampersand to your enumeration variable to allow write access. – FreeAsInBeer Jul 30 '12 at 21:20
4

Here is a link to a solution that illustrates the comment by @FreeAsInBeer [link](https://stackoverflow.com/a/7617643/9090980) with respect to the ampersand. – DanimalReks Jun 04 '19 at 21:52
Is this destructive of the original array? Is there a clean functional paradigm way to do this that produces an entirely new array without the value? – Urasquirrel Sep 10 '21 at 21:04
What is the best approach for case insensitivity (key1, Key1, KEY1 etc.)? – Vineet Sajwan Jun 27 '23 at 06:18

score 32 · Answer 2 · edited Sep 06 '16 at 08:38

32

Use this function to remove specific arrays of keys without modifying the original array:

function array_except($array, $keys) {
  return array_diff_key($array, array_flip((array) $keys));   
}

First param pass all array, second param set array of keys to remove.

For example:

$array = [
    'color' => 'red', 
    'age' => '130', 
    'fixed' => true
];
$output = array_except($array, ['color', 'fixed']);
// $output now contains ['age' => '130']

edited Sep 06 '16 at 08:38

userlond

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answered Sep 01 '15 at 10:56

Bafi

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7

1

you need to close your quotes on `$output = array_except($array_1, ['color', 'fixed']);` – Abraham Brookes Jul 27 '16 at 07:05
plus one! functional! – Urasquirrel Sep 10 '21 at 21:06
I needed reverse functionality, is there in built functionality? ```php function array_extract($array, $keys) { return array_intersect_key($array, array_flip((array) $keys)); } $output = array_extract($array, ['color', 'fixed']); print_r($output); //Array ( [color] => red [fixed] => 1 ); ``` – Sahil Kashyap Dec 31 '21 at 08:47

score 27 · Answer 3 · edited Aug 16 '22 at 00:03

27

Use unset():

unset($array['key1']);

edited Aug 16 '22 at 00:03

Pang

9,564
146
81
122

answered Jun 16 '10 at 13:15

cletus

616,129
168
910
942

score 10 · Answer 4 · edited Jan 25 '16 at 17:34

10

Using unset:

unset($array['key1'])

edited Jan 25 '16 at 17:34

user229044

232,980
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answered Jun 16 '10 at 13:15

Cristian

198,401
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score 7 · Answer 5 · answered Apr 19 '18 at 14:32

Consider this array:

$arr = array("key1" => "value1", "key2" => "value2", "key3" => "value3", "key4" => "value4");

To remove an element using the array key:

// To unset an element from array using Key:
unset($arr["key2"]);
var_dump($arr);
// output: array(3) { ["key1"]=> string(6) "value1" ["key3"]=> string(6) "value3" ["key4"]=> string(6) "value4" }

To remove element by value:

// remove an element by value:
$arr = array_diff($arr, ["value1"]);
var_dump($arr);
// output: array(2) { ["key3"]=> string(6) "value3" ["key4"]=> string(6) "value4" }

read more about array_diff: http://php.net/manual/en/function.array-diff.php

To remove an element by using index:

array_splice($arr, 1, 1);
var_dump($arr);
// array(1) { ["key3"]=> string(6) "value3" }

read more about array_splice: http://php.net/manual/en/function.array-splice.php

score 4 · Answer 6 · edited Apr 07 '22 at 20:06

4

You may need two or more loops depending on your array:

$arr[$key1][$key2][$key3]=$value1; // ....etc

foreach ($arr as $key1 => $values) {
  foreach ($values as $key2 => $value) {
  unset($arr[$key1][$key2]);
  }
}

edited Apr 07 '22 at 20:06

Suraj Lulla

489
5
12

answered Mar 06 '15 at 05:28

Ruth VBA

49
1

score 3 · Answer 7 · answered Mar 13 '21 at 09:42

you can do it using Laravel helpers:

first helper, method Arr::except:

$array = ['name' => 'Desk', 'price' => 100];

$filtered = Arr::except($array, ['price']);

// ['name' => 'Desk']

second helper: method Arr::pull

$array = ['name' => 'Desk', 'price' => 100];

$name = Arr::pull($array, 'name');

// $name: Desk

// $array: ['price' => 100]

How can I remove a key and its value from an associative array?

7 Answers7

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