Non Repeating Random Numbers

Is there a way to select a fair number of random numbers and guarantee that there were no repeats and thus each number was selected once. I essentially need to shuffle the numbers 1-1800

Hi Jackson,

The following code should be good for your purpose. You may try it in the Flexsim script window. You will see outputs in the output console.

treenode tmpNode = node("/Tools/TEMP",model());
if(!objectexists(tmpNode)){
    nodeinsertinto(node("/Tools",model()));
    setnodename(last(node("/Tools",model())),"TEMP");
    tmpNode = last(node("/Tools",model()));
}
int maxNum = 10;
for(int i=1;i<=maxNum;i++){
    nodeinsertinto(tmpNode);
    nodeadddata(last(tmpNode), DATATYPE_NUMBER);
    setnodenum(last(tmpNode), i);
}
intarray rndNums = makearray(maxNum);
int cnt = 1;
while(content(tmpNode)!=0){
    int chosenRank = duniform(1, maxNum-cnt+1);
    rndNums[cnt] = getnodenum(rank(tmpNode, chosenRank));
    destroyobject(rank(tmpNode, chosenRank));
    cnt++;
}
for(i=1;i<=maxNum;i++){
    pd(rndNums[i]);pr();
}

I guess this is what happens when we both try to answer the same post with code. We both came up with something that works, but they work completely differently. Alan's method makes treenodes with sequential values, then adds their values randomly to an array as it deletes them from the tree. My method makes a sequential array, then swaps each one at least once to a random position:

int arraysize=1800;
intarray myarray=makearray(arraysize);
int x;
for(x=1;x<=arraysize;x++){
    myarray[x]=x;
}
// myarray is now 1,2,3,4,5...
for(x=1;x<=arraysize;x++){pd(myarray[x]);pc(',');}pr();//print the array
//swap each element with a random element at least once, (on average twice)
int temp;
int swapindex;
for(x=1;x<=arraysize;x++){
    swapindex=duniform(1,arraysize);
    temp=myarray[swapindex];
    myarray[swapindex]=myarray[x];
    myarray[x]=temp;
}
for(x=1;x<=arraysize;x++){pd(myarray[x]);pc(',');}pr();//print the array

My code runs faster

Hi Alex,

You code is very interesting and use a complete different approach that I may never think of. And as you said, you code probably runs a bit faster. But I think my code is easier to understand. See I do not even need to put any comment into the code.