Generate 3 different random numbers without duplic

I want to generate three random numbers between 0 and 6, and pass them to global variables. this is what I have:

set one to floor(random(6))

set two to floor(random(6))

set three to floor(random(6))

I can?t figure out how to make sure that none of these three numbers are the same.

I know a method but not now to apply it to construct 2.

• Put the first value into an array,

• start a while loop that doesn't close until the size of the array matches the number of values you need.

• generate a random number...
• compare it to everything in the array...
• if it doesn't match anything, add it to the array...

You can do the array method, but here's a lazier way:

dl.dropbox.com/u/19702035/randomstuff.capx

It works for a smaller amount of numbers, but if you wanna do more the array method works better. I'll show you how to do that too if you want.

There's no while loop in c2.

The only sure way I know to do a sampling without replacement is to make a list of your sample, pick one at random, delete the sample from the list.

I showed an implementation not long ago.

It went a bit like that:

global sampleCount = 3  // number of... number you want
+System: on start of layout
  -> Array: set size to sampleCount,1,1
+On What you want
  Local text list = "0,1,2,3,4,5,6" 
  +repeat sampleCount times
    -> Array: set value at loopindex to int((tokenat(list,floor(random(tokencount(list,","))),",")))
    -> System: set list to replace(list,str(Array.At(loopindex)),"")
    -> System: set list to replace(list,",,",",")
    -> System: set list to (left(list,0,1) = ",") ? right(list,len(list)-1) : list
    -> System: set list to (right(list,len(list-1),1) = ",") ? left(list,len(list)-1) : list

    -> System: set list to replace(list,Array.At(loopindex),"")

    -> System: set list to replace(list,",,",",")

    -> System: set list to (left(list,0,1) = ",") ? right(list,len(list)-1) : list

    -> System: set list to (right(list,len(list-1),1) = ",") ? left(list,len(list)-1) : list

... Aaaaand that's the not lazy way. <img src="smileys/smiley36.gif" border="0" align="middle" />

SullyTheStrange

You're way is ugly :D... But indeed pretty neat for the question asked

However I would add another global variable that goes from 0 to 1 once one!=two!=three

To tell the game "ok the variables are now good we can continue"

You made me realize there's indeed a while in c2... The gameloop itself (:

Yann:

I'm not sure, but looking at your implementation, it looks like it would cause problems with sets that contained values which have substrings which match other values, eg:

1,2,3,4,5,6,7,8,9,10,11

ex: program picks 1

set list to replace(list,str(Array.At(loopindex)),"")

Replace will wipe out the '1' string in '1', '10', and '11'

A while back when I was working on a text-parser with C2, I encountered a similar problem and ended up having to manually traverse and remove without the replace expression.

A way to handle that that I have used in the past is to use a leading and trailing comma in the list, then not use the first and last tokens, which would be "".

Here is Yann's example tweaked with that in mind.

global sampleCount = 3  // number of... number you want
+System: on start of layout
  -> Array: set size to sampleCount,1,1
+On What you want
  Local text list = ",0,1,2,3,4,5,6," 
  +repeat sampleCount times
    -> Array: set value at loopindex to int((tokenat(list,int(random(tokencount(list,",")-2)+1),",")))
    -> System: set list to replace(list , ","&str(Array.At(loopindex))&"," , ",")

cacotigon

Yep you're super right and I felt into that kind of issue. I solved it by using zerofill numbers.

I think I used r0j0's way too once. Don't remember, I tend to reinvent the wheel sometimes :D

with zerofill you don't fall into the substring issue

"001,002,003,010,110,102,etc"

if you replace(str,"001","") you won't have any issue

and you can still int("003") into 3 with no problem.

But yeah... use r0j0's way... it's the cleanest (:

This post has been super helpful in assisting me in understanding tokens and how to randomly pull from them. I am having one hang up with Yann's example. In the line

"System: set list to (left(list,0,1) = ",") ? right(list,len(list)-1) : list"

Construct is telling me that left can only have to parameters? What am I missing? been beating my head on this for a full day trying to understand. And Special thanks to Yann! always popping up in the forums I have searched with some intense tech responses.

ASBanks

yeah probably made a mistake in the two last lines

-> System: set list to (left(list,0,1) = ",") ? right(list,len(list)-1) : list
-> System: set list to (right(list,len(list-1),1) = ",") ? left(list,len(list)-1) : list

-> System: set list to (left(list,1) = ",") ? right(list,len(list)-1) : list
-> System: set list to (right(list,1) = ",") ? left(list,len(list)-1) : list

I think the best and easiest way to do this without a lot extra steps like the token way is to use arrays. Plus its scalable for any amount of numbers/strings/etc.

Make an array and fill it with all your possible choices (in this case numbers) pick a random number from the size of the array and then get that number out of the array and store it however you want to store your 3 picked numbers. Then remove that number from the array.

Once its removed from the array it wont be able to be picked a 2nd time cause it no longer exists unless you added it more than once to the array

Awesome! thanks Guys!