+

1.001.001.001.001.501.000.50

Hover & click on the images for description

Description

Description:

Add two Numbers, concatenate two Arrays or two Strings, or create a copy of an Array or HashMap.

⚠

Array copy methods ARRAY + [] and + ARRAY have different behaviours:

• ARRAY + [] creates copy of the 1st dimension, but preserves references in other dimensions (shallow copy).
• + ARRAY clones every element, so if the array is multi-dimensional, the created copy contains no references (deep copy).

See Example 6.

Groups:

MathArraysHashMapStrings

Syntax 1

Syntax:

numberA + numberB

Parameters:

numberA: Number

numberB: Number

Return Value:

Number - the sum of numberA and numberB

Syntax 2

Syntax:

+ number

Parameters:

number: Number

Return Value:

Number - the value of the parameter number

Syntax 3

Syntax:

arrayA + arrayB

Parameters:

arrayA: Array

arrayB: Array

Return Value:

Array - a new array filled with arrayA and arrayB elements, in that order

Syntax 4

Syntax:

stringA + stringB

Parameters:

stringA: String

stringB: String

Return Value:

String - a string concatenating stringA and stringB

Syntax 5

Syntax:

+ array

Parameters:

array: Array

Return Value:

Array - a new instance of the provided array filled with same elements (deep copy)

2.04

Syntax 6

Syntax:

+ hashMap

Parameters:

hashMap: HashMap

Return Value:

HashMap - a new instance of the provided HashMap filled with the same key-value pairs (deep copy)

Examples

Example 1:

5 + 3 // returns 8 -5 + -3 // returns -8

Example 2:

+ 2 // returns 2 + -7 // returns -7

Example 3:

_arrayA = [1,2,3]; _arrayB = [3,4,5]; _arrayAB = _arrayA + _arrayB; // _arrayAB = [1,2,3,3,4,5] // _arrayA and _arrayB remain unchanged

Example 4:

_result = "Hello" + " " + "there"; // "Hello there"

Example 5:

_arrayA = [1,2,3]; _arrayB = + _arrayA; _arrayB set [0, 99]; // _arrayA = [1,2,3], _arrayB = [99,2,3]

Example 6:

Shallow copy with ARRAY + []:

private _subArray = [1, 2, 3]; private _array1 = [_subArray, 1, 2, 3]; private _array2 = _array1 + []; _array2 select 0 set [0, "oops"]; hint str _subArray; // ["oops", 2, 3]

Deep copy with + ARRAY:

private _subArray = [1, 2, 3]; private _array1 = [_subArray, 1, 2, 3]; private _array2 = + _array1; _array2 select 0 set [0, "oops"]; hint str _subArray; // [1, 2, 3]

Additional Information

See also:

Operators pushBack append merge

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