Difference between revisions of "random"
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Lou Montana (talk  contribs) 
Lou Montana (talk  contribs) m (Some wiki formatting) 

(19 intermediate revisions by the same user not shown)  
Line 79:  Line 79:  
r4= [[Number]] from 0 (included) to 1 (excluded)  r4= [[Number]] from 0 (included) to 1 (excluded)  
−  x1= <  +  x1= <sqf>_rNumber = random 1;</sqf> 
−  x2= <  +  x2= <sqf>_rNumber = random 10;</sqf> 
x3= Generate a random position inside a circle (see also [[Example Code: Random Area Distribution]])  x3= Generate a random position inside a circle (see also [[Example Code: Random Area Distribution]])  
−  <  +  <sqf>_center getPos [_radius * sqrt random 1, random 360];</sqf> 
x4= Select a random value from an array:  x4= Select a random value from an array:  
−  <  +  <sqf>_array = ["apples", "pears", "bananas", "M16"]; 
−  _random = _array  +  _random = _array select floor random count _array; // Before Arma 2 
−  _random = _array  +  _random = _array call BIS_fnc_selectRandom; // Since Arma 2 
−  _random =  +  _random = selectRandom _array; // Since Arma 3 v1.56</sqf> 
seealso= [[selectRandom]] [[selectRandomWeighted]]  seealso= [[selectRandom]] [[selectRandomWeighted]]  
Line 103:  Line 103:  
<dd class="note">  <dd class="note">  
Random selections including negative numbers can be obtained via:  Random selections including negative numbers can be obtained via:  
−  <  +  <sqf>_Xrnd = round(random 200) 100;</sqf> 
This will yield numbers between 100 and 100.  This will yield numbers between 100 and 100.  
Line 109:  Line 109:  
* The number returned is unlikely to be a whole number.<br>  * 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]]:  To return a whole number use either '''[[round]]''', '''[[ceil]]''' or '''[[floor]]''' together with [[random]]:  
−  <  +  <sqf> 
−  x =  +  x = round (random 5) // will return 0, 1, 2, 3, 4 or 5. (nonuniform distribution, 0 and 5 are half as likely to be selected than any of the other numbers) 
−  x =  +  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)  
+  </sqf>  
</dd>  </dd>  
Latest revision as of 16:39, 13 May 2022
Description
 Description:

Syntax 1 generates a random floating point value Syntax 2 generates a Gaussian Distribution^{[1]}. It uses the same method as setTriggerTimeout command and is quite useful for e.g spawning loot, making more valuable items more rare Syntax 3 generates a seedbased random number Syntax 4 generates a seedbased random noise (not Perlin) texture based on provided seed and returning the value at supplied coordinates  Groups:
 Math
Syntax 1
Syntax 2
 Syntax:
 random [min, mid, max]
 Parameters:
 min: Number
 mid: Number
 max: Number
 Return Value:
 Number in range from min to max, weighted by mid
Syntax 3
 Syntax:
 seed random x
 Parameters:
 seed: Number  an integer. Any float value will be truncated (e.g 0.9, 0.1, 0.1 or 0.9 will be read as 0)
 x: Number
 Return Value:
 Number from 0 (included) to x (excluded)
Syntax 4
 Syntax:
 seed random [x, y]
 Parameters:
 seed: Number
 x: Number  x texture position
 y: Number  y texture position
 Return Value:
 Number from 0 (included) to 1 (excluded)
Examples
 Example 1:
 Example 2:
 Example 3:
 Generate a random position inside a circle (see also Example Code: Random Area Distribution)
 Example 4:
 Select a random value from an array:
Additional Information
 See also:
 selectRandom selectRandomWeighted
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:
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.
x = round (random 5) // will return 0, 1, 2, 3, 4 or 5. (nonuniform 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%
 ↑ 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.
Categories:
 Scripting Commands
 Introduced with Operation Flashpoint version 1.00
 Operation Flashpoint: New Scripting Commands
 Operation Flashpoint: Scripting Commands
 Operation Flashpoint: Elite: Scripting Commands
 ArmA: Armed Assault: Scripting Commands
 Arma 2: Scripting Commands
 Arma 2: Operation Arrowhead: Scripting Commands
 Take On Helicopters: Scripting Commands
 Arma 3: Scripting Commands
 Command Group: Math