Random number push array

1

Hi
i have been racking my head for days over random number no repeats

iam doing a bingo caller game iam stuck with random number with no repeats
this is the code snipplet im using

var num:Number = Math.ceil(Math.random()*90);

i use the timer class to call a number every few seconds

how do i do it with no repeats,

do i have to put the numbers into a array then pull the numbers from the array,
here is some code i have found but can’t get it to work

var firstarray:Array = new Array();
for(var u:Number = 1; u <= 90; u++){
firstarray.push(u);
}
var secondarray:Array = new Array(); 
while (firstarray.length >0) {
var num:Number = Math.floor(Math.random()*firstarray.length);
secondarray.push(firstarray[num]);
firstarray.splice(num,1);
} 
while (myNumbArray.length>0) {
  myRandArray.push( myNumbArray.splice(randRange(0, myNumbArray.length-1), 1));
}
trace (num);
}

please help i just can’t get my head baround it