forEach

1.001.001.001.001.501.000.50

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Description

Description:

Executes the given command(s) on every item of an Array or a HashMap.

Since Arma 2, the variable _x is always private to the forEach block so it is safe to nest them (see Example 8).

Groups:

Program FlowArraysHashMap

Syntax

Syntax:

code forEach array

Parameters:

code: String in Operation Flashpoint and Armed Assault, Code since Armed Assault - available variables:

• _x: iterated item
• _forEachIndex: item's index

array: Array - The array to iterate over

Return Value:

Anything - Will return the value of last executed statement

2.02

Alternative Syntax

Syntax:

code forEach hashMap

Parameters:

code: Code - code applied to each key-value pair - available variables:

• _x: key
• _y: value
• _forEachIndex: iteration number

hashMap : HashMap - The HashMap to iterate over

Return Value:

Anything - Will return the value of last executed statement

Examples

Example 1:

// SQF { _x setDamage 1 } forEach units player;

; SQS "_x setDammage 1" forEach units player

Example 2:

This command can also easily be used to execute a single command multiple times without respect to the array items - see also for

{ player addMagazine "30Rnd_556x45_Stanag" } forEach [1, 2, 3, 4]; // equivalent to for "_i" from 1 to 4 do { player addMagazine "30Rnd_556x45_Stanag" };

Example 3:

You can also use multiple commands in the same block:

{ _x setCaptive true; removeAllWeapons _x; doStop _x; } forEach units group this;

Example 4:

To get the index of a forEach loop, use _forEachIndex:

{ systemChat str _forEachIndex; } forEach ["a", "b", "c"]; // will return: "0", "1", "2" in systemChat messages

Example 5:

Iterating a HashMap's _forEachIndex:

// shows "0, k1, v1", "1, k2, v2" in systemChat messages { systemChat format ["%1, %2, %3", _forEachIndex, _x, _y]; } forEach createHashMapFromArray [ ["k1", "v1"], ["k2", "v2"] ];

Example 6:

findIf equivalent for HashMap:

private _resultKey = { if (_y isEqualTo "wantedValue") exitWith { _x }; "" } forEach _hashmap;

Example 7:

Array is edited by reference:

_arr1 = [1,2,3]; _arr2 = [6,7,8]; _arr3 = [0]; { _x set [1, "changed"] } forEach [_arr1, _arr2, _arr3]; // _arr1 = [1, "changed", 3] // _arr2 = [6, "changed", 8] // _arr3 = [0, "changed"]

Example 8:

{ private _verticalValue = _x; // needed, otherwise _horizontalValues' _x made this one inaccessible { [_x, _verticalValue] call TAG_fnc_doSomething; } forEach _horizontalValues; } forEach _verticalValues;

Additional Information

See also:

Control Structures for apply while select findIf count forEachReversed

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

Dedmen - c

Posted on Nov 28, 2017 - 13:46 (UTC)

Be careful when deleting (deleteAt) elements from an Array while you iterate over it.
_forEachIndex will not move to reflect your change.
The forEach code is doing the same as

private _forEachIndex = 0; while { _forEachIndex < count _array } do { (_array select _forEachIndex) call code; _forEachIndex = _forEachIndex + 1; };

So if you delete your current element from the array the other elements will shift forward. Meaning you skip one element.
Example:

_array = [1,2,3,4,5,6]; { _array deleteAt _forEachIndex } forEach _array;

After the first iteration your Array will be [2,3,4,5,6] and the _forEachIndex will be 1.
So on next iteration you get the element at index 1 which will be 3. So you've just skipped the 2.
So in the end you will only iterate over 1, 3 and 6.

Samatra - c

Posted on Apr 02, 2023 - 09:04 (UTC)

Deleting elements with deleteAt while walking through array with forEach does not work as you might expect it. Use new forEachReversed command for it. Check its examples for details.