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m (Text replacement - " \|([ps][0-9]+) *= " to " |$1= ")
m (Text replacement - "<tt>([^= ]+)<\/tt>" to "{{hl|$1}}")
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|descr= Add two [[Number]]s, concatenate two [[Array]]s or two [[String]]s, or create a copy of an Array or [[HashMap]].
|descr= Add two [[Number]]s, concatenate two [[Array]]s or two [[String]]s, or create a copy of an Array or [[HashMap]].


{{Feature | Warning | [[Array]] copy methods <tt>ARRAY + []</tt> and <tt>+ ARRAY</tt> have different behaviours:
{{Feature | Warning | [[Array]] copy methods {{hl|ARRAY + []}} and {{hl|+ ARRAY}} have different behaviours:
* <tt>ARRAY + []</tt> creates copy of the 1st dimension, but preserves references in other dimensions ({{Wikipedia|Object copying#Shallow copy|shallow copy}}).
* {{hl|ARRAY + []}} creates copy of the 1st dimension, but preserves references in other dimensions ({{Wikipedia|Object copying#Shallow copy|shallow copy}}).
* <tt>+ ARRAY</tt> clones every element, so if the array is multi-dimensional, the created copy contains no references ({{Wikipedia|Object copying#Deep copy|deep copy}}).
* {{hl|+ ARRAY}} clones every element, so if the array is multi-dimensional, the created copy contains no references ({{Wikipedia|Object copying#Deep copy|deep copy}}).
See [[#Example_6|Example 6]].}}
See [[#Example_6|Example 6]].}}


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_arrayB [[set]] [0, 99]; {{cc|_arrayA {{=}} [1,2,3], _arrayB {{=}} [99,2,3]}}</code>  
_arrayB [[set]] [0, 99]; {{cc|_arrayA {{=}} [1,2,3], _arrayB {{=}} [99,2,3]}}</code>  


|x6= Shallow copy with <tt>ARRAY + []</tt>:
|x6= Shallow copy with {{hl|ARRAY + []}}:
<code>[[private]] _subArray = [1, 2, 3];
<code>[[private]] _subArray = [1, 2, 3];
[[private]] _array1 = [_subArray, 1, 2, 3];
[[private]] _array1 = [_subArray, 1, 2, 3];
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[[hint]] [[str]] _subArray; {{cc|["oops", 2, 3]}}</code>
[[hint]] [[str]] _subArray; {{cc|["oops", 2, 3]}}</code>


Deep copy with <tt>+ ARRAY</tt>:
Deep copy with {{hl|+ ARRAY}}:
<code>[[private]] _subArray = [1, 2, 3];
<code>[[private]] _subArray = [1, 2, 3];
[[private]] _array1 = [_subArray, 1, 2, 3];
[[private]] _array1 = [_subArray, 1, 2, 3];

Revision as of 00:17, 16 November 2021

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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:
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)

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

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