如何创建不重复的随机数数组

Question

I've created a lotto number generator and am having trouble making sure no two sets of numbers come out the same. I want to first check that the next generated number doesn't match a previous one in the array, if it does then generate a new number.

The code: https://codesandbox.io/s/billowing-leaf-oqdt3?file=/index.html

Answer 1

You can do it step by step by replacing what you have line 46 by:

// Get a random number
var rnd = rand(high);
// If it is already in the array, get another
while (numList.includes(rnd)) {
    rnd = rand(high);
}
// Now you know the value is unique, so you can add it to the list.
numList.unshift(rnd);

Answer 2

use a hash:

var numberHash = {}
var num1=generateNum(numberHash);
var num2=generateNum(numberHash);

function generateNum(numberHash) {
  var num = rand();
  while(numberHash[num]) {
    num = rand();
  }
  numberHash[num]=true;
  return num;
}