+: Difference between revisions

Revision as of 15:34, 10 May 2022

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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:

Math Arrays HashMap Strings

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

@@ Line 83: / Line 83: @@
 |r6= [[HashMap]] - A new instance of the provided [[HashMap]] filled with the same key-value pairs ({{Wikipedia|Object copying#Deep copy|deep copy}})
-|x1= <code>5 [[+]]  3	{{cc|returns  8}}
+|x1= <sqf>
--5 [[+]] -3	{{cc|returns -8}}</code>
++  3	// returns  8
+-5 + -3	// returns -8
+</sqf>
-|x2= <code>[[+]]  2	{{cc|returns  2}}
+|x2= <sqf>
-[[+]] -7	{{cc|returns -7}}</code>
++  2	// returns  2
++ -7	// returns -7
+</sqf>
-|x3= <code>_arrayA = [1,2,3];
+|x3= <sqf>
+_arrayA = [1,2,3];
 _arrayB = [3,4,5];
-_arrayAB = _arrayA + _arrayB; {{cc|_arrayAB {{=}} [1,2,3,3,4,5]}}
+_arrayAB = _arrayA + _arrayB; // _arrayAB = [1,2,3,3,4,5]
-{{cc|_arrayA and _arrayB remain unchanged}}</code>
+// _arrayA and _arrayB remain unchanged
+</sqf>
-|x4= <code>_result = "Hello" + " " + "there"; {{cc|"Hello there"}}</code>
+|x4= <sqf>_result = "Hello" + " " + "there"; // "Hello there"</sqf>
-|x5= <code>_arrayA = [1,2,3];
+|x5= <sqf>
+_arrayA = [1,2,3];
 _arrayB = + _arrayA;
-_arrayB [[set]] [0, 99]; {{cc|_arrayA {{=}} [1,2,3], _arrayB {{=}} [99,2,3]}}</code>
+_arrayB set [0, 99]; // _arrayA = [1,2,3], _arrayB = [99,2,3]
+</sqf>
 |x6= Shallow copy with {{hl|ARRAY + []}}:
-<code>[[private]] _subArray = [1, 2, 3];
+<sqf>
-[[private]] _array1 = [_subArray, 1, 2, 3];
+private _subArray = [1, 2, 3];
-[[private]] _array2 = _array1 + [];
+private _array1 = [_subArray, 1, 2, 3];
-_array2 [[select]] 0 [[set]] [0, "oops"];
+private _array2 = _array1 + [];
-[[hint]] [[str]] _subArray; {{cc|["oops", 2, 3]}}</code>
+_array2 select 0 set [0, "oops"];
+hint str _subArray; // ["oops", 2, 3]
+</sqf>
 Deep copy with {{hl|+ ARRAY}}:
-<code>[[private]] _subArray = [1, 2, 3];
+<sqf>
-[[private]] _array1 = [_subArray, 1, 2, 3];
+private _subArray = [1, 2, 3];
-[[private]] _array2 = + _array1;
+private _array1 = [_subArray, 1, 2, 3];
-_array2 [[select]] 0 [[set]] [0, "oops"];
+private _array2 = + _array1;
-[[hint]] [[str]] _subArray; {{cc|[1, 2, 3]}}</code>
+_array2 select 0 set [0, "oops"];
+hint str _subArray; // [1, 2, 3]
+</sqf>
 |seealso= [[Operators]] [[pushBack]] [[append]] [[merge]]
 }}