Difference between revisions of "random"

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{{Command|Comments=
 
{{Command|Comments=
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| ofp |Game name=
 
| ofp |Game name=
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|gr1= Math |GROUP1=
 
|gr1= Math |GROUP1=
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|[[Image:bellcurve.jpg|right|200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<br>
 
|[[Image:bellcurve.jpg|right|200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<br>
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* allowing to generate semi-random number based on provided seed ('''Alternative Syntax 2''')
 
* allowing to generate semi-random number based on provided seed ('''Alternative Syntax 2''')
 
* generating pseudo-random [https://en.wikipedia.org/wiki/Perlin_noise noise texture] based on provided seed and returning a single number between 0 (included) and 1 (excluded) at supplied ''x'' and ''y'' coordinates ('''Alternative Syntax 3''') |Description=
 
* generating pseudo-random [https://en.wikipedia.org/wiki/Perlin_noise noise texture] based on provided seed and returning a single number between 0 (included) and 1 (excluded) at supplied ''x'' and ''y'' coordinates ('''Alternative Syntax 3''') |Description=
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| [[random]] x |Syntax=
 
| [[random]] x |Syntax=
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| [[Number]] |Return value=
 
| [[Number]] |Return value=
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|s2= [[random]] [min, mid, max] {{Since|arma3|1.55.133393|y}} |Syntax 2=
 
|s2= [[random]] [min, mid, max] {{Since|arma3|1.55.133393|y}} |Syntax 2=
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|p24= max: [[Number]] |Parameter 24=
 
|p24= max: [[Number]] |Parameter 24=
 
|r2= [[Number]]|Return value 2=
 
|r2= [[Number]]|Return value 2=
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|s3= seed [[random]] x {{Since|arma3|1.67.139663|y}} |Syntax 3=
 
|s3= seed [[random]] x {{Since|arma3|1.67.139663|y}} |Syntax 3=
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|p42= x: [[Number]] |Parameter 42=
 
|p42= x: [[Number]] |Parameter 42=
 
|r3= [[Number]] - value from 0 to x |Return value 3=
 
|r3= [[Number]] - value from 0 to x |Return value 3=
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|s4= seed [[random]] [x, y] {{Since|arma3|1.67.139663|y}} |Syntax 4=
 
|s4= seed [[random]] [x, y] {{Since|arma3|1.67.139663|y}} |Syntax 4=
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|p64= y: [[Number]] |Parameter 64=
 
|p64= y: [[Number]] |Parameter 64=
 
|r4= [[Number]] - value from 0 to 1 |Return value 4=
 
|r4= [[Number]] - value from 0 to 1 |Return value 4=
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|x1= <code>_rNumber = [[random]] 1;</code> |Example 1=
 
|x1= <code>_rNumber = [[random]] 1;</code> |Example 1=
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{{cc|{{Since|arma3|1.55.133393}}}}
 
{{cc|{{Since|arma3|1.55.133393}}}}
 
_random = [[selectRandom]] _array;</code>  |Example 4=
 
_random = [[selectRandom]] _array;</code>  |Example 4=
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| [[selectRandom]], [[selectRandomWeighted]] |See also=
 
| [[selectRandom]], [[selectRandomWeighted]] |See also=

Revision as of 03:17, 17 January 2021

Hover & click on the images for description

Description

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


Since Arma 3 v1.55.133393 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)

Since Arma 3 v1.67.139663 two alternative syntaxes are available:

  • allowing to generate semi-random number based on provided seed (Alternative Syntax 2)
  • generating pseudo-random noise texture based on provided seed and returning a single number between 0 (included) and 1 (excluded) at supplied x and y coordinates (Alternative Syntax 3)
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 position on the Perlin noise texture
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

Notes

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.