javascript - 从数组中随机选择唯一项目并添加到新数组的问题

Question

您能否看一下此演示，并让我知道如何从每个国家/地区的 countries 数组中选择 25 个唯一 项目

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

正如我所说，每个数组都有 25 个唯一项非常重要。这是我正在处理的示例:

$(function () {

    var countries = ["Afghanistan", "Albania", "Algeria", "Andorra", "Angola", "Anguilla", "Antigua & Barbuda", "Argentina", "Armenia", "Aruba", "Australia", "Austria", "Azerbaijan", "Bahamas", "Bahrain", "Bangladesh", "Barbados", "Belarus", "Belgium", "Belize", "Benin", "Bermuda", "Bhutan", "Bolivia", "Bosnia & 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 & Miquelon", "Samoa", "San Marino", "Satellite", "Saudi Arabia", "Senegal", "Serbia", "Seychelles", "Sierra Leone", "Singapore", "Slovakia", "Slovenia", "South Africa", "South Korea", "Spain", "Sri Lanka", "St Kitts & Nevis", "St Lucia", "St Vincent", "St. Lucia", "Sudan", "Suriname", "Swaziland", "Sweden", "Switzerland", "Syria", "Taiwan", "Tajikistan", "Tanzania", "Thailand", "Timor L'Este", "Togo", "Tonga", "Trinidad & Tobago", "Tunisia", "Turkey", "Turkmenistan", "Turks & 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>

Answer 1

1. 使用 while 循环不断迭代，直到确定非重复项。
2. 使用indexOf()判断数组中是否存在该国家
3. 完成while循环后，push(它应该是保证唯一的)

<小时/>

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 & Barbuda", "Argentina", "Armenia", "Aruba", "Australia", "Austria", "Azerbaijan", "Bahamas", "Bahrain", "Bangladesh", "Barbados", "Belarus", "Belgium", "Belize", "Benin", "Bermuda", "Bhutan", "Bolivia", "Bosnia & 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 & Miquelon", "Samoa", "San Marino", "Satellite", "Saudi Arabia", "Senegal", "Serbia", "Seychelles", "Sierra Leone", "Singapore", "Slovakia", "Slovenia", "South Africa", "South Korea", "Spain", "Sri Lanka", "St Kitts & Nevis", "St Lucia", "St Vincent", "St. Lucia", "Sudan", "Suriname", "Swaziland", "Sweden", "Switzerland", "Syria", "Taiwan", "Tajikistan", "Tanzania", "Thailand", "Timor L'Este", "Togo", "Tonga", "Trinidad & Tobago", "Tunisia", "Turkey", "Turkmenistan", "Turks & 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>