Question

我想在带有for循环的数组中插入15个随机值。这是我的代码，但它不起作用......

var cardArray[]; //set up empty array

for (var i = 0; i <= 15; i++) {
    var NumberCard = Math.floor((Math.random() * 50) + 1);
    var NameCard = Math.floor((Math.random() * 4) + 1);

    cardArray[i] = "Number Card: " + NumberCard + " Name Card: "+ NameCard;
}
for (var i = 0; i <= 15; i+=2) {
    document.writeln(cardArray[i] + "<br />");
}

Answer 1

你没有很好地定义cardArray，它应该是=＆gt; var cardArray = []

另外，为什么你在第二个循环中做i+=2？你想跳过值吗？我将其更改为i++

var cardArray = []; //set up empty array

for (var i = 0; i <= 15; i++) {
    var NumberCard = Math.floor((Math.random() * 50) + 1);
    var NameCard = Math.floor((Math.random() * 4) + 1);

    cardArray[i] = "Number Card: " + NumberCard + " Name Card: "+ NameCard;
}
for (var i = 0; i <= 15; i++) {
    document.writeln(cardArray[i] + "<br />");
}

Answer 2

因为你需要先定义数组，就像这样！

var cardArray = new Array(15); //set up empty array

for (var i = 0; i <= 15; i++) {
    var NumberCard = Math.floor((Math.random() * 50) + 1);
    var NameCard = Math.floor((Math.random() * 4) + 1);

    cardArray[i] = "Number Card: " + NumberCard + " Name Card: "+ NameCard;
}
for (var i = 0; i <= 15; i+=2) {
    document.writeln(cardArray[i] + "<br />");
}

Answer 3

问题出在你的声明中。变化

var cardArray[];

到

var cardArray = [];

var cardArray = []; //set up empty array

for (var i = 0; i <= 15; i++) {
    var NumberCard = Math.floor((Math.random() * 50) + 1);
    var NameCard = Math.floor((Math.random() * 4) + 1);

    cardArray[i] = "Number Card: " + NumberCard + " Name Card: "+ NameCard;
}
for (var i = 0; i <= 15; i+=2) {
    document.writeln(cardArray[i] + "<br />");
}

Answer 4

＆＃13;

var cards = [];

function getRand(min, max) {
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

for (var i = 0; i <= 15; i++) {
  cards.push("Number Card: " + getRand(1, 50) + " Name Card: " + getRand(1, 4));
  var div = document.createElement("div");
  div.innerHTML = cards[i];
  document.body.appendChild(div);
}

＆＃13;

使用循环将值插入数组

4 个答案: