I need to know how to iterate through an array without repeating

Question

I want to randomly iterate an array runs while randomly selecting a mainSamplers and a secondarySamplers. The below code works but will repeat runs and I need to keep running it over and over.

// program to get a random samplestrong text

function getRandomItem(arr) {

  // get random index value
  const randomIndex = Math.floor(Math.random() * arr.length);

  // get random item
  const item = arr[randomIndex];

  return item;
}

let runs = ["W1", "W2/W3", "W4/W6", "W5", "W7/W8", "E1/E2", "E3/E4", "E5/RB", "SA/SB", "LT",
  "LR1", "LR2", "LR3", "LR4", "LR5", "LR6", "LR7", "LR8", "Mullet Creek"];
let mainSamplers = ["RAB", "CJ", "AMR", "ND", "RB", "ED", "SD", "MEF"];
let secondarySamplers = ["KD", "SA", "AF", "JT", "EV"];



//1st sample set
const result1 = getRandomItem(runs) + " " + getRandomItem(mainSamplers) + " " +
  getRandomItem(secondarySamplers);

console.log("Run" + " " + "Samplers");
console.log(result1);
  // need to run this as many times as there are runs and not repeat the runs

So shuffle the runs array and pop from it until it is empty. And when you run out create a new instance and reshuffle. — epascarello, Aug 29 '22 at 18:04
Create a copy of the original array and shuffle it: https://www.w3docs.com/snippets/javascript/how-to-randomize-shuffle-a-javascript-array.html — ControlAltDel, Aug 29 '22 at 18:08
Does this answer your question? [How to efficiently randomly select array item without repeats?](https://stackoverflow.com/questions/17891173/how-to-efficiently-randomly-select-array-item-without-repeats) — pilchard, Aug 29 '22 at 18:15

score 0 · Accepted Answer · answered Aug 29 '22 at 18:12

You can delete each random element from run.

// program to get a random samplestrong text

function getRandomItem(arr) {
  // get random index value
  const randomIndex = Math.floor(Math.random() * arr.length);

  // get random item
  const item = arr[randomIndex];

  return item;
}

let runs = ["W1", "W2/W3", "W4/W6", "W5", "W7/W8", "E1/E2", "E3/E4", "E5/RB", "SA/SB", "LT",
  "LR1", "LR2", "LR3", "LR4", "LR5", "LR6", "LR7", "LR8", "Mullet Creek"
];
let mainSamplers = ["RAB", "CJ", "AMR", "ND", "RB", "ED", "SD", "MEF"];
let secondarySamplers = ["KD", "SA", "AF", "JT", "EV"];


console.log("Run" + " " + "Samplers");
while (runs.length) {
  //1st sample set
  let val = getRandomItem(runs);
  const result1 = val + " " + getRandomItem(mainSamplers) + " " +
    getRandomItem(secondarySamplers);

  console.log(result1);
  
  runs.splice(runs.indexOf(val), 1);
}

Thanks for your answer. Do you know how to make my final list of the random runs list only select a certain number of random mainSamplers instead of just randomly selecting one. I would need some to be selected 3 times and some only twice. I want them randomly selected but with some being selected 3 times (RAB, CJ, AMR, MH, ED, ND) and the others only selected 2 times through the randomly selected runs array. — RAB, Sep 15 '22 at 11:38

I need to know how to iterate through an array without repeating

1 Answers1