deleteAt

1.32

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Description

Description:

Removes array element at the given index and returns removed element (modifies the original array, just like resize or set).

ⓘ

For the non-HashMap command variant, if the index is a negative Number, it will not issue error making it ideal for using with find (see Example 2) or findIf (see Example 3). If the index is an Array with a negative Number, the deletion will be done from the back of the source array (see Example 4)

Groups:

ArraysHashMap

Syntax

Syntax:

array deleteAt index

Parameters:

array: Array

index: Number or 2.16 Array in format [index], where index is a single positive, zero or negative Number (see a note in description)

Return Value:

Anything - returns the deleted element or Nothing

2.02

Alternative Syntax

Syntax:

hashMap deleteAt key

Parameters:

hashMap: HashMap

key: HashMapKey

Return Value:

Anything

Examples

Example 1:

_arr = [1,2,3]; _rem = _arr deleteAt 1; hint str [_rem, _arr]; // [2, [1, 3]]

Example 2:

_arr = [1,2,3]; _arr deleteAt (_arr find 0); // non existent item hint str _arr; // [1,2,3] _arr deleteAt (_arr find 2); // existent item hint str _arr; // [1,3]

Example 3:

_arr = [1,2,3]; _arr deleteAt (_arr findIf {(_x % 5) == 0}); // Remove first number that's divisible by 5 hint str _arr; // [1,2,3] _arr deleteAt (_arr findIf {(_x % 2) == 0}); // Remove first number that's divisible by 2 hint str _arr; // [1,3]

Example 4:

_arr = [1,2,3,4]; _arr deleteAt [-1]; // Remove the last array element systemchat str _arr; // [1,2,3] _arr deleteAt [-3]; // Remove the first array element systemchat str _arr; // [2,3]

Additional Information

See also:

deleteRange set resize select in find findIf toArray toString forEach count pushBack pushBackUnique apply append sort param params arrayIntersect splitString joinString

Notes

Report bugs on the Feedback Tracker and/or discuss them on the Arma Discord or on the Forums.
Only post proven facts here! Add Note

Heeeere's Johnny! - c

Posted on Oct 15, 2014 - 16:55 (UTC)

_array deleteAt 0;

is almost 60x faster than

_array = _array - [_array select 0]

(Tested with an array of 10.000 strings, iterating through it using a for-from-to-do loop)

Highhead - c

Posted on Mar 04, 2016 - 15:58 (UTC)

Deleting from an array with foreach and _foreachIndex variable is tricky. The array is being altered, the _foreachIndex won't keep up and other elements in the array will be skipped and in worst case not being deleted. If you delete elements from an array in descending order (using while or for) it will work.

Igneous01 - c

Posted on Feb 09, 2017 - 22:45 (UTC)

To expand on Highheads comment above - this is because forEach implements iterators to traverse a collection, which are read only by definition. The variable _x is an iterator that points to the current item in the collection. Trying to alter _x will have no effect.

private _array = [1,2,3,4,5,6,7,8]; { _x = 2; } forEach _array // _array is still [1,2,3,4,5,6,7,8]

When trying to use deleteAt inside forEach, the behaviour would be undefined as you are invalidating the iterator reference, and it will not know how to traverse to the next element. In short, only use forEach when reading data from an array. For more info about iterators, see C++ Iterators.

Freghar - c

Posted on Feb 01, 2021 - 18:06 (UTC)

As you would expect from a simple array implementation,

array deleteAt (count array - 1);

is virtually zero cost (0.0005ms on an array of 1000000 elements), while

array deleteAt 0;

is very performance heavy (0.7ms on the same huge array).