# Creating unique numbers from random numbers generator

Discussion in 'World Editor Help' started by GamerSmurf, Apr 13, 2017.

1. ### GamerSmurfNew Member

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I am creating a TD where each wave starts with a "funny" message from the creeps. The map has 30 waves but I have maybe 50 funny messages I like to use at random.
So I need to create a trigger, that sets a variable FunnyString to a random number between 1 and 50. For the next wave FunnyString should be a random number between 1 and 50, but not a number that has been selected before. This has to be done for all 30 waves.

Anyone got an idea to create this?

2. ### Accname2D-Graphics enthusiast

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1) Create a variable FunnyNumber[] as an array with 50 elements.
2) Fill FunnyNumber to FunnyNumber with the number from 1 to 50 (you can do that with a for-each-Integer-A loop)
3) Shuffle all 50 numbers using the common array shuffle algorithm: (pseudo code)
Code:
```  shuffle(arr) {
iteration = length of (arr)
while (iteration > 1) {
index = random number between 0 and iteration (inclusive);
tempValue = arr[index];
arr[index] = arr[i];
arr[i] = tmp
iteration += 1
}
}
```
4) You now have your numbers randomly shuffled. Just pick them one after another.

Alternative without shuffling:
1) Create a variable FunnyNumber[] as an array with 50 elements.
2) Fill FunnyNumber to FunnyNumber with the number from 1 to 50 (you can do that with a for-each-Integer-A loop)
3) Have another variable FunnyNumberCount which is initialized with 50
4) Every time you need a random number you pick an index randomly between 1 and FunnyNumberCount (inclusive)
5) You switch the numbers at FunnyNumber[index] and FunnyNumber[FunnyNumberCount]
6) You decrement FunnyNumberCount by 1
7) This way you have moved the randomly picked number to the end of the array and you decreased the logical length of the array effectively "removing" the number from the array.

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3. ### GamerSmurfNew Member

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Thank you for a very quickly respond. I didn't expect that and I have created a trigger myself after creating this thread, that somehow seems to work in the first attempt.
It's far from as elegant and complicated as yours, but if I get any problems with my trigger I'll use one of your solutions. Thank you

4. ### GamerSmurfNew Member

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Hi again Accname
My solution didn't work after all. The solution with the shuffle algorithm seems like the most "simple" one, but I don't know how to use that kind of code in the Trigger Editor.

For the none shuffling solution I know how to do the first 3 steps but I don't know how to do step 4 and 5. Could you elaborate step 4 and 5?

5. ### Accname2D-Graphics enthusiast

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Here, I just created these two simple triggers for you:
Trigger:
• Init
• Events
• Map initialization
• Conditions
• Actions
• Set LastValidIndex = 50
• For each (Integer A) from 1 to LastValidIndex, do (Actions)
• Loop - Actions
• Set NumberArray[(Integer A)] = (Integer A)

Trigger:
• Test
• Events
• Player - Player 1 (Red) types a chat message containing <Empty String> as A substring
• Conditions
• Actions
• Set RandomIndex = (Random integer number between 1 and LastValidIndex)
• Game - Display to (All players) the text: (RandomIndex= + (String(RandomIndex)))
• Set RandomNumber = NumberArray[RandomIndex]
• Game - Display to (All players) the text: (RandomNumber= + (String(RandomNumber)))
• Set NumberArray[RandomIndex] = NumberArray[LastValidIndex]
• Set LastValidIndex = (LastValidIndex - 1)
• Game - Display to (All players) the text: (LastValidIndex= + (String(LastValidIndex)))
• Game - Display to (All players) the text: <Empty String>

The used variables are:
RandomIndex - integer
RandomNumber - integer
NumberArray - integer array
LastValidIndex - integer

Whenever you send a chat message you will get a new random number between 1 and 50 but you will never get the same number twice. This will only work 50 times after which the triggers will bug out. You could add additional code to fool-proof the entire thing if you think it is necessary. Otherwise just dont call it more often than 50 times.

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6. ### GamerSmurfNew Member

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Thank you again. I think the use of number, index and array have confused me a bit. Now everything works as intended