Issue on Randomly Select Unique Items From An Array and Add To New Arrays

Question

Can you please take a look at this demo and let me know how I can Select 25 Unique items from the countries array for each of

    var player1 = [];
    var player2 = [];
    var player3 = [];
    var player4 = [];

As I said it is important to have the 25 Unique items is each of arrays.Here is the sample which I am working on:

$(function () {

    var countries = ["Afghanistan", "Albania", "Algeria", "Andorra", "Angola", "Anguilla", "Antigua &amp; Barbuda", "Argentina", "Armenia", "Aruba", "Australia", "Austria", "Azerbaijan", "Bahamas", "Bahrain", "Bangladesh", "Barbados", "Belarus", "Belgium", "Belize", "Benin", "Bermuda", "Bhutan", "Bolivia", "Bosnia &amp; Herzegovina", "Botswana", "Brazil", "British Virgin Islands", "Brunei", "Bulgaria", "Burkina Faso", "Burundi", "Cambodia", "Cameroon", "Cape Verde", "Cayman Islands", "Chad", "Chile", "China", "Colombia", "Congo", "Cook Islands", "Costa Rica", "Cote D Ivoire", "Croatia", "Cruise Ship", "Cuba", "Cyprus", "Czech Republic", "Denmark", "Djibouti", "Dominica", "Dominican Republic", "Ecuador", "Egypt", "El Salvador", "Equatorial Guinea", "Estonia", "Ethiopia", "Falkland Islands", "Faroe Islands", "Fiji", "Finland", "France", "French Polynesia", "French West Indies", "Gabon", "Gambia", "Georgia", "Germany", "Ghana", "Gibraltar", "Greece", "Greenland", "Grenada", "Guam", "Guatemala", "Guernsey", "Guinea", "Guinea Bissau", "Guyana", "Haiti", "Honduras", "Hong Kong", "Hungary", "Iceland", "India", "Indonesia", "Iran", "Iraq", "Ireland", "Isle of Man", "Israel", "Italy", "Jamaica", "Japan", "Jersey", "Jordan", "Kazakhstan", "Kenya", "Kuwait", "Kyrgyz Republic", "Laos", "Latvia", "Lebanon", "Lesotho", "Liberia", "Libya", "Liechtenstein", "Lithuania", "Luxembourg", "Macau", "Macedonia", "Madagascar", "Malawi", "Malaysia", "Maldives", "Mali", "Malta", "Mauritania", "Mauritius", "Mexico", "Moldova", "Monaco", "Mongolia", "Montenegro", "Montserrat", "Morocco", "Mozambique", "Namibia", "Nepal", "Netherlands", "Netherlands Antilles", "New Caledonia", "New Zealand", "Nicaragua", "Niger", "Nigeria", "Norway", "Oman", "Pakistan", "Palestine", "Panama", "Papua New Guinea", "Paraguay", "Peru", "Philippines", "Poland", "Portugal", "Puerto Rico", "Qatar", "Reunion", "Romania", "Russia", "Rwanda", "Saint Pierre &amp; Miquelon", "Samoa", "San Marino", "Satellite", "Saudi Arabia", "Senegal", "Serbia", "Seychelles", "Sierra Leone", "Singapore", "Slovakia", "Slovenia", "South Africa", "South Korea", "Spain", "Sri Lanka", "St Kitts &amp; Nevis", "St Lucia", "St Vincent", "St. Lucia", "Sudan", "Suriname", "Swaziland", "Sweden", "Switzerland", "Syria", "Taiwan", "Tajikistan", "Tanzania", "Thailand", "Timor L'Este", "Togo", "Tonga", "Trinidad &amp; Tobago", "Tunisia", "Turkey", "Turkmenistan", "Turks &amp; Caicos", "Uganda", "Ukraine", "United Arab Emirates", "United Kingdom", "Uruguay", "Uzbekistan", "Venezuela", "Vietnam", "Virgin Islands (US)", "Yemen", "Zambia", "Zimbabwe"];


    var player1 = [];
    var player2 = [];
    var player3 = [];
    var player4 = [];


    $("#load").on("click", function () {

        for (var i = 0; i < 25; ++i) {
            var randomIndex = Math.floor(Math.random() * countries.length);
            player1.push(countries[randomIndex]);
        }
        console.log(player1);

    });


});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button type="button" id="load" class="btn btn-default">Load</button>

score 2 · Answer 1 · answered Jun 23 '15 at 23:00

Use a while loop to keep iterating until a non-duplicate has been determined.
Use indexOf() to determine whether the country exists in the array or not
After the while loop is done, push (It should be a guaranteed unique)

for (var i = 0; i < 25; ++i) {
      var randomIndex = Math.floor(Math.random() * countries.length);
      while (player1.indexOf(countries[randomIndex]) > -1) {
        randomIndex = Math.floor(Math.random() * countries.length);

      }
      player1.push(countries[randomIndex]);
    }

$(function() {

  var countries = ["Afghanistan", "Albania", "Algeria", "Andorra", "Angola", "Anguilla", "Antigua &amp; Barbuda", "Argentina", "Armenia", "Aruba", "Australia", "Austria", "Azerbaijan", "Bahamas", "Bahrain", "Bangladesh", "Barbados", "Belarus", "Belgium", "Belize", "Benin", "Bermuda", "Bhutan", "Bolivia", "Bosnia &amp; Herzegovina", "Botswana", "Brazil", "British Virgin Islands", "Brunei", "Bulgaria", "Burkina Faso", "Burundi", "Cambodia", "Cameroon", "Cape Verde", "Cayman Islands", "Chad", "Chile", "China", "Colombia", "Congo", "Cook Islands", "Costa Rica", "Cote D Ivoire", "Croatia", "Cruise Ship", "Cuba", "Cyprus", "Czech Republic", "Denmark", "Djibouti", "Dominica", "Dominican Republic", "Ecuador", "Egypt", "El Salvador", "Equatorial Guinea", "Estonia", "Ethiopia", "Falkland Islands", "Faroe Islands", "Fiji", "Finland", "France", "French Polynesia", "French West Indies", "Gabon", "Gambia", "Georgia", "Germany", "Ghana", "Gibraltar", "Greece", "Greenland", "Grenada", "Guam", "Guatemala", "Guernsey", "Guinea", "Guinea Bissau", "Guyana", "Haiti", "Honduras", "Hong Kong", "Hungary", "Iceland", "India", "Indonesia", "Iran", "Iraq", "Ireland", "Isle of Man", "Israel", "Italy", "Jamaica", "Japan", "Jersey", "Jordan", "Kazakhstan", "Kenya", "Kuwait", "Kyrgyz Republic", "Laos", "Latvia", "Lebanon", "Lesotho", "Liberia", "Libya", "Liechtenstein", "Lithuania", "Luxembourg", "Macau", "Macedonia", "Madagascar", "Malawi", "Malaysia", "Maldives", "Mali", "Malta", "Mauritania", "Mauritius", "Mexico", "Moldova", "Monaco", "Mongolia", "Montenegro", "Montserrat", "Morocco", "Mozambique", "Namibia", "Nepal", "Netherlands", "Netherlands Antilles", "New Caledonia", "New Zealand", "Nicaragua", "Niger", "Nigeria", "Norway", "Oman", "Pakistan", "Palestine", "Panama", "Papua New Guinea", "Paraguay", "Peru", "Philippines", "Poland", "Portugal", "Puerto Rico", "Qatar", "Reunion", "Romania", "Russia", "Rwanda", "Saint Pierre &amp; Miquelon", "Samoa", "San Marino", "Satellite", "Saudi Arabia", "Senegal", "Serbia", "Seychelles", "Sierra Leone", "Singapore", "Slovakia", "Slovenia", "South Africa", "South Korea", "Spain", "Sri Lanka", "St Kitts &amp; Nevis", "St Lucia", "St Vincent", "St. Lucia", "Sudan", "Suriname", "Swaziland", "Sweden", "Switzerland", "Syria", "Taiwan", "Tajikistan", "Tanzania", "Thailand", "Timor L'Este", "Togo", "Tonga", "Trinidad &amp; Tobago", "Tunisia", "Turkey", "Turkmenistan", "Turks &amp; Caicos", "Uganda", "Ukraine", "United Arab Emirates", "United Kingdom", "Uruguay", "Uzbekistan", "Venezuela", "Vietnam", "Virgin Islands (US)", "Yemen", "Zambia", "Zimbabwe"];


  var player1 = [];
  var player2 = [];
  var player3 = [];
  var player4 = [];


  $("#load").on("click", function() {

    for (var i = 0; i < 25; ++i) {
      var randomIndex = Math.floor(Math.random() * countries.length);
      while (player1.indexOf(countries[randomIndex]) > -1) {
        randomIndex = Math.floor(Math.random() * countries.length);

      }
      player1.push(countries[randomIndex]);
    }
    console.log(player1);

  });


});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button type="button" id="load" class="btn btn-default">Load</button>

Thanks AmmarCSE but this is loading the items in only one of the arrays. can you please let me know how to do this for there playes arrays? in the same time? — Suffii, Jun 23 '15 at 23:04
As I asked in the post already I need to load data into all 4 arrays var `player1 = []; var player2 = []; var player3 = []; var player4 = [];` — Suffii, Jun 23 '15 at 23:05

stephenspann · Accepted Answer · 2015-06-23T23:15:45.360

make a temporary copy of the array, and then use array.splice() to remove an item from the array. Then you can get another random index based on the new length... do this 25 times for each player.

If only one player can have a country, you can persist the temporary array until all 4 players have their countries.

example:

$(function () {

    var countries = ["Afghanistan", "Albania", "Algeria", "Andorra", "Angola", "Anguilla", "Antigua &amp; Barbuda", "Argentina", "Armenia", "Aruba", "Australia", "Austria", "Azerbaijan", "Bahamas", "Bahrain", "Bangladesh", "Barbados", "Belarus", "Belgium", "Belize", "Benin", "Bermuda", "Bhutan", "Bolivia", "Bosnia &amp; Herzegovina", "Botswana", "Brazil", "British Virgin Islands", "Brunei", "Bulgaria", "Burkina Faso", "Burundi", "Cambodia", "Cameroon", "Cape Verde", "Cayman Islands", "Chad", "Chile", "China", "Colombia", "Congo", "Cook Islands", "Costa Rica", "Cote D Ivoire", "Croatia", "Cruise Ship", "Cuba", "Cyprus", "Czech Republic", "Denmark", "Djibouti", "Dominica", "Dominican Republic", "Ecuador", "Egypt", "El Salvador", "Equatorial Guinea", "Estonia", "Ethiopia", "Falkland Islands", "Faroe Islands", "Fiji", "Finland", "France", "French Polynesia", "French West Indies", "Gabon", "Gambia", "Georgia", "Germany", "Ghana", "Gibraltar", "Greece", "Greenland", "Grenada", "Guam", "Guatemala", "Guernsey", "Guinea", "Guinea Bissau", "Guyana", "Haiti", "Honduras", "Hong Kong", "Hungary", "Iceland", "India", "Indonesia", "Iran", "Iraq", "Ireland", "Isle of Man", "Israel", "Italy", "Jamaica", "Japan", "Jersey", "Jordan", "Kazakhstan", "Kenya", "Kuwait", "Kyrgyz Republic", "Laos", "Latvia", "Lebanon", "Lesotho", "Liberia", "Libya", "Liechtenstein", "Lithuania", "Luxembourg", "Macau", "Macedonia", "Madagascar", "Malawi", "Malaysia", "Maldives", "Mali", "Malta", "Mauritania", "Mauritius", "Mexico", "Moldova", "Monaco", "Mongolia", "Montenegro", "Montserrat", "Morocco", "Mozambique", "Namibia", "Nepal", "Netherlands", "Netherlands Antilles", "New Caledonia", "New Zealand", "Nicaragua", "Niger", "Nigeria", "Norway", "Oman", "Pakistan", "Palestine", "Panama", "Papua New Guinea", "Paraguay", "Peru", "Philippines", "Poland", "Portugal", "Puerto Rico", "Qatar", "Reunion", "Romania", "Russia", "Rwanda", "Saint Pierre &amp; Miquelon", "Samoa", "San Marino", "Satellite", "Saudi Arabia", "Senegal", "Serbia", "Seychelles", "Sierra Leone", "Singapore", "Slovakia", "Slovenia", "South Africa", "South Korea", "Spain", "Sri Lanka", "St Kitts &amp; Nevis", "St Lucia", "St Vincent", "St. Lucia", "Sudan", "Suriname", "Swaziland", "Sweden", "Switzerland", "Syria", "Taiwan", "Tajikistan", "Tanzania", "Thailand", "Timor L'Este", "Togo", "Tonga", "Trinidad &amp; Tobago", "Tunisia", "Turkey", "Turkmenistan", "Turks &amp; Caicos", "Uganda", "Ukraine", "United Arab Emirates", "United Kingdom", "Uruguay", "Uzbekistan", "Venezuela", "Vietnam", "Virgin Islands (US)", "Yemen", "Zambia", "Zimbabwe"];

    // make a copy of the countries array
    var countriesTemp = countries.slice();

    var player1 = [];
    var player2 = [];
    var player3 = [];
    var player4 = [];

    function getCountries(playerArray) {
        for (var i = 0; i < 25; ++i) {
            var randomIndex = Math.floor(Math.random() * countriesTemp.length);
            playerArray.push(countriesTemp[randomIndex]);
            countriesTemp.splice(randomIndex, 1);
        }
    }

    $("#load").on("click", function () {

        getCountries(player1);
        console.log(player1);
        getCountries(player2);
        console.log(player2);
        getCountries(player3);
        console.log(player3);
        getCountries(player4);
        console.log(player4);

    });


});

Hi spanndemic, thanks for reply but this is still loading only on `player1` then how about the other array? — Suffii, Jun 23 '15 at 23:12
you could abstract the logic into a function, then call the function for each player array — stephenspann, Jun 23 '15 at 23:12

score 0 · Answer 3 · edited May 23 '17 at 11:51

0

I'd check out Generating random whole numbers in JavaScript in a specific range?

From there you can do some boolean logic to make sure none of the integers are the same, or add the value to an array and use the contains method.

edited May 23 '17 at 11:51

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answered Jun 23 '15 at 23:01

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Issue on Randomly Select Unique Items From An Array and Add To New Arrays

3 Answers3