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

Given an associative array:

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

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

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

Use unset():

unset($array['key1']);

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

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

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

Using unset:

unset($array['key1'])

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']