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back to [[Scripting_Reference#R|COMREF]]
{{RV|type=command


<h2 style="color:#000066">'''random ''x'''''</h2>
|game1= ofp
|version1= 1.00


|game2= ofpe
|version2= 1.00


'''Operand types:'''
|game3= arma1
|version3= 1.00


'''x:''' [[Number]]
|game4= arma2
|version4= 1.00


'''Type of returned value:'''
|game5= arma2oa
|version5= 1.50


[[Number]]
|game6= tkoh
|version6= 1.00


'''Description:'''
|game7= arma3
|version7= 0.50


Random real value from 0 to '''x'''.
|gr1= Math


|descr= [[Image:bellcurve.jpg|right|200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<br><br>
{{GVI|arma3|1.56}} alternative syntax is added, allowing the definition of {{Wikipedia|Normal_distribution|Gaussian Distribution}}<ref>Technically, it is a rescaled {{Wikipedia|Bates_distribution|Bates distribution}} with n = 4. The distribution is split in two at its midpoint and scaled linearly such that its maximum lies at the specified midpoint.</ref> params. Uses the same method as [[setTriggerTimeout]] command. Quite useful for spawning loot for example, making more valuable items more rare ({{HashLink|#Alternative Syntax 1}})<br><br>
{{GVI|arma3|1.68}} two alternative syntaxes are available:
* allowing to generate {{Wikipedia|Random seed|seed-based}} random number based on provided seed ({{HashLink|#Alternative Syntax 2}})
* generating {{Wikipedia|Random seed|seed-based}} random noise texture based on provided seed and returning a single number between 0 (included) and 1 (excluded) at supplied ''x'' and ''y'' coordinates ({{HashLink|#Alternative Syntax 3}})


'''Example:'''
|s1= [[random]] x


_rNumber = '''random''' 1
|p1= x: [[Number]]


|r1= [[Number]]


'''Comments'''
|s2= [[random]] [min, mid, max] {{Since|arma3|1.56|y}}


Be careful using random numbers in multiplayer, each client will come up with something different.
|p21= [min, mid, max]: [[Array]]
See multiplayer tutorials for more general information about locality.


|p22= min: [[Number]]


The number returned is unlikely to be a whole number (e.g. 1,  4, 76, etc.).
|p23= mid: [[Number]]


To return a whole number combine [[random]] and [[mod]].
|p24= max: [[Number]]
 
|r2= [[Number]]
 
|s3= seed [[random]] x {{Since|arma3|1.68|y}}
 
|p41= seed: [[Number]]
 
|p42= x: [[Number]]
 
|r3= [[Number]] - Value from 0 to x
 
|s4= seed [[random]] [x, y] {{Since|arma3|1.68|y}}
 
|p61= seed: [[Number]]
 
|p62= [x, y]: [[Array]] - texture position (''not'' a Perlin noise)
 
|p63= x: [[Number]]
 
|p64= y: [[Number]]
 
|r4= [[Number]] - Value from 0 to 1
 
|x1= <code>_rNumber = [[random]] 1;</code>
 
|x2= <code>_rNumber = [[random]] -10;</code>
 
|x3= Generate a random position inside a circle (see also [[Example Code: Random Area Distribution]])
<code>_center [[getPos]] [<nowiki/>_radius * [[sqrt]] [[random]] 1, [[random]] 360];</code>
 
|x4= To select random value from an array:
<code>_array = ["apples", "pears", "bananas", "M16"];
_random = _array [[select]] [[floor]] [[random]] [[count]] _array;
{{cc|{{Since|arma3|1.56}}}}
_random = [[selectRandom]] _array;</code>
 
|seealso= [[selectRandom]], [[selectRandomWeighted]]
}}
 
<dl class="command_description">
 
<dt></dt>
<dd class="notedate">Posted on July 12, 2015 - 20:32 (UTC)</dd>
<dt class="note">[[User:Hcpookie|Hcpookie]]</dt>
<dd class="note">
Random selections including negative numbers can be obtained via:
<code>_Xrnd = round(random 200) -100;</code>
 
This will yield numbers between -100 and 100.
* Be careful using random numbers in multiplayer, each client will come up with a different result. See multiplayer tutorials for more general information about locality.
* The number returned is unlikely to be a whole number.<br>
To return a whole number use either '''[[round]]''', '''[[ceil]]''' or '''[[floor]]''' together with [[random]]:
<code>x = round(random 5) will return 0,1,2,3,4 or 5. (non-uniform distribution, 0 and 5 are half as likely to be selected than any of the other numbers)
x = floor(random 5) will return 0,1,2,3 or 4.  (uniform distribution, all numbers have the same probability of being selected)
x = ceil(random 5) will return  0,1,2,3,4 or 5. (0 is very unlikely, but possible, as ceil 0 is 0)</code>
</dd>
 
<dd class="notedate">Posted on July 22, 2018 - 12:58 (UTC+2)</dd>
<dt class="note">[[User:Lou Montana|Lou Montana]]</dt>
<dd class="note">
{| class="wikitable"
|+ Repartition comparison
! Formula
! 0
! 1
! 2
! 3
! 4
! 5
! 6
! 7
! 8
! 9
|-
| [[floor]] [[random]] 10;
| 10%
| 10%
| 10%
| 10%
| 10%
| 10%
| 10%
| 10%
| 10%
| 10%
|-
| [[floor]] [[random]] [0, 5, 10]
| 0%
| 2%
| 7%
| 17%
| 25%
| 25%
| 17%
| 7%
| 2%
| 0%
|-
| [[floor]] [[random]] [0, 10, 0]
| 0%
| 0%
| 1%
| 2%
| 5%
| 9%
| 14%
| 19%
| 24%
| 26%
|-
| [[floor]] [[random]] [0, 10, 5]
| 0%
| 0%
| 0%
| 1%
| 2%
| 5%
| 9%
| 16%
| 28%
| 38%
|}
</dd>
 
</dl>

Revision as of 17:05, 13 June 2021

Logo A0.png1.00ofpe logo.png1.00Logo A1 black.png1.00Logo A2.png1.00A2 OA Logo.png1.50tkoh logo small.png1.00Arma 3 logo black.png0.50
Hover & click on the images for description

Description

Description:
bellcurve.jpg
Random real (floating point) value from 0 (inclusive) to x (not inclusive).

Arma 3 logo black.png1.56 alternative syntax is added, allowing the definition of Gaussian Distribution[1] params. Uses the same method as setTriggerTimeout command. Quite useful for spawning loot for example, making more valuable items more rare (Alternative Syntax 1)

Arma 3 logo black.png1.68 two alternative syntaxes are available:

Groups:
Math

Syntax 1

Syntax:
random x
Parameters:
x: Number
Return Value:
Number

Syntax 2

Syntax:
random [min, mid, max] Template:Since
Parameters:
[min, mid, max]: Array
min: Number
mid: Number
max: Number
Return Value:
Number

Syntax 3

Syntax:
seed random x Template:Since
Parameters:
seed: Number
x: Number
Return Value:
Number - Value from 0 to x

Syntax 4

Syntax:
seed random [x, y] Template:Since
Parameters:
seed: Number
[x, y]: Array - texture position (not a Perlin noise)
x: Number
y: Number
Return Value:
Number - Value from 0 to 1

Examples

Example 1:
_rNumber = random 1;
Example 2:
_rNumber = random -10;
Example 3:
Generate a random position inside a circle (see also Example Code: Random Area Distribution) _center getPos [_radius * sqrt random 1, random 360];
Example 4:
To select random value from an array: _array = ["apples", "pears", "bananas", "M16"]; _random = _array select floor random count _array; // Template:Since _random = selectRandom _array;

Additional Information

See also:
selectRandomselectRandomWeighted

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
Posted on July 12, 2015 - 20:32 (UTC)
Hcpookie
Random selections including negative numbers can be obtained via: _Xrnd = round(random 200) -100; This will yield numbers between -100 and 100.
  • Be careful using random numbers in multiplayer, each client will come up with a different result. See multiplayer tutorials for more general information about locality.
  • The number returned is unlikely to be a whole number.
To return a whole number use either round, ceil or floor together with random: x = round(random 5) will return 0,1,2,3,4 or 5. (non-uniform distribution, 0 and 5 are half as likely to be selected than any of the other numbers) x = floor(random 5) will return 0,1,2,3 or 4. (uniform distribution, all numbers have the same probability of being selected) x = ceil(random 5) will return 0,1,2,3,4 or 5. (0 is very unlikely, but possible, as ceil 0 is 0)
Posted on July 22, 2018 - 12:58 (UTC+2)
Lou Montana
Repartition comparison
Formula 0 1 2 3 4 5 6 7 8 9
floor random 10; 10% 10% 10% 10% 10% 10% 10% 10% 10% 10%
floor random [0, 5, 10] 0% 2% 7% 17% 25% 25% 17% 7% 2% 0%
floor random [0, 10, 0] 0% 0% 1% 2% 5% 9% 14% 19% 24% 26%
floor random [0, 10, 5] 0% 0% 0% 1% 2% 5% 9% 16% 28% 38%
  1. ↑ Technically, it is a rescaled Bates distribution with n = 4. The distribution is split in two at its midpoint and scaled linearly such that its maximum lies at the specified midpoint.
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