How to select a number randomly in a range but with considerable difference

simran

I want to select a random number within a range, but say number that was gets generated is 'x', next time i want the number to be at least x(+)or(-) 20. How can I achieve this?

OZApps

have you tried

a = math.random(20, x)
http://docs.giderosmobile.com/reference/lua/math/random#math.random

ar2rsawseen

Or did you mean something like this?

math.random(x, x+40)-20

Or like this?

if math.random() >= 0.5 then x = x + 20 else x = x - 20 end

OZApps

@ar2rsawseen, it can also be used as

math.random(20) + x

which would ensure that the minimum lower value is never zero, but x.

hgvyas123

by this

local myTemnum = 50   function displayRand()   local rand = math.random(myTemnum-10,myTemnum+10) myTemnum = rand print("your random num is with minimum range of 20 with last number is ",myTemnum)     myTemnum = myTemnum +30   end   stage:addEventListener(Event.ENTER_FRAME, displayRand) Timer.delayedCall(500,function() stage:removeEventListener(Event.ENTER_FRAME, displayRand) end)

HubertRonald

if x is a continuous variable so

x = 20*math.random() + x

P(x=0) = 0

:x

elseif x is a discrete variable so

@ar2rsawseen, it can also be used as

math.random(20) + x

which would ensure that the minimum lower value is never zero, but x.

end

simran

Thank you all It's such a great place :-h

OZApps

if x is a continuous variable so

x = 20*math.random() + x

P(x=0) = 0

:x

elseif x is a discrete variable so

@ar2rsawseen, it can also be used as

math.random(20) + x

which would ensure that the minimum lower value is never zero, but x.

end

@HubertRonald, you are correct that when x = 0, the value can be 0. However the point here was to achieve a random value starting with a minimum value of x.

HubertRonald

@HubertRonald, you are correct that when x = 0, the value can be 0. However the point here was to achieve a random value starting with a minimum value of x.

Hi! @OZApps
P(x=0) = 0 mean than probability of that x will be zero is zero because x~[min, max] (x is a pseudo random continuous variable) there are infinities values then:

1/math.huge = 0

So no matter the initial value of x or after, because it is guaranteed to never x will be zero.

For example, we are make a classic: "Asteroids Game" and we define the rotational speed of our rocks that appear in the game in a range of [-20, 20] and we always want our rocks are rotating:

x: Rotational speed

First case: x is a discrete value:

left_or_right = random.math(0,1)   if left_or_right == 0 then x = math.random(-20,-1)   elseif left_or_right == 1 then x = math.random(1,20) end   -- or any algorithm like a sort ([-20,-19,...,-1,1,...,19,20]) zero isn't in this list -- or another algorithm

Second case: x is a continuous variable (Uniform Distribution Continuous)

x = 40*math.random() - 20 -- x will not be zero: P(x=0) = 0

I know that program has some art because there is no one right way to do a code (and such flexibility that I love :x), just wanted to bring some of my views with my folks.

But most important is that our friend @simran found his solution

Cheers

simran

That insight was helpful Thank you