Posted By: Ben
Is there an easy way to delete an element from an array using PHP, such that
foreach ($array) no longer includes that element?
I thought that setting it to
null would do it, but apparently it does not work.
There are different ways to delete an array element, where some are more useful for some specific tasks than others.
Deleting a single array element
If you know the value and don’t know the key to delete the element you can use
array_search() to get the key. This only works if the element does not occur more than once, since
array_search returns the first hit only.
Note that when you use
unset() the array keys won’t change. If you want to reindex the keys you can use
unset(), which will convert all keys to numerically enumerated keys starting from 0.
$array = [0 => "a", 1 => "b", 2 => "c"]; unset($array); // ↑ Key which you want to delete
[  => a  => c ]
If you use
array_splice() the keys will automatically be reindexed, but the associative keys won’t change — as opposed to
array_values(), which will convert all keys to numerical keys.
array_splice() needs the offset, not the key, as the second parameter.
$array = [0 => "a", 1 => "b", 2 => "c"]; array_splice($array, 1, 1); // ↑ Offset which you want to delete
[  => a  => c ]
array_splice(), same as
unset(), take the array by reference. You don’t assign the return values of those functions back to the array.
Deleting multiple array elements
If you want to delete multiple array elements and don’t want to call
array_splice() multiple times you can use the functions
array_diff_key() depending on whether you know the values or the keys of the elements which you want to delete.
If you know the values of the array elements which you want to delete, then you can use
array_diff(). As before with
unset() it won’t change the keys of the array.
$array = [0 => "a", 1 => "b", 2 => "c", 3 => "c"]; $array = array_diff($array, ["a", "c"]); // └────────┘ // Array values which you want to delete
[  => b ]
If you know the keys of the elements which you want to delete, then you want to use
array_diff_key(). You have to make sure you pass the keys as keys in the second parameter and not as values. Keys won’t reindex.
$array = [0 => "a", 1 => "b", 2 => "c"]; $array = array_diff_key($array, [0 => "xy", "2" => "xy"]); // ↑ ↑ // Array keys which you want to delete
[  => b ]
If you want to use
array_splice() to delete multiple elements with the same value you can use
array_keys() to get all the keys for a specific value and then delete all elements.