Question

我有一个名字数组，选择三个随机名称并将它们放入一个新数组然后打印出来。我怎么能这样做，所以我永远不会使用IF语句获得重复的名称？截至目前，我有时会在生成随机名称时两次使用相同的名称。

＆＃13;

<!DOCTYPE html>
<html>
<head>
	<title>Students</title>
	<script type="text/javascript">
		
		window.onload = btn;

		function btn() {
			document.getElementById("btn").onclick = showStudents;
		}

		var text = "";
		var randomStudents = []; // Empty array
		var students = ["Henning", "Torstein", "Elias", "Ådne", "Dag", "Sander", "Zuz", "Braum", "Sverre", "Kayn", "Katarina", "Vayne"];

		function showStudents() {

			// Count to three
			for (var i = 0; i < 3; i++) {
					// Take three random elements from students array and put into empty array
					randomStudents += students[Math.floor(Math.random() * students.length)] + "<br/>";
			}
			// Print out the array with random names
			document.getElementById("print").innerHTML = randomStudents;
		}

	</script>
</head>
<body>
<button id="btn">Show Students</button>
<p id="print"></p>
</body>
</html>

＆＃13;

Answer 1

找到学生后，从阵列中删除该学生。这样，下一次就不会出现了。

function showStudents() {
  // Copy the array of students
  var tmpStudents = students.concat([]);

  // Count to three
  for (var i = 0; i < 3; i++) {
    // Get the random index
    var randomIndex = Math.floor(Math.random() * tmpStudents.length);

    // Take three random elements from students array and put into empty array
    randomStudents += tmpStudents[randomIndex] + "<br/>";

    // Remove the student from the array
    students.splice(randomIndex, 1);
  }

  // Print out the array with random names
  document.getElementById("print").innerHTML = randomStudents;
}

Answer 2

我建议使用while循环。当你生成一个不同的名字时，很难猜到。试试这个

for (var i = 0; i < 3; i++) {
    // Take random element from students array
    studentToAdd = students[Math.floor(Math.random() * students.length)];

    // checks if student is already included. Generates another student if true
    while (randomStudents.includes(studentToAdd) === true) {
       studentToAdd = students[Math.floor(Math.random() * students.length)];
    }

    // adds generated student
    randomStudents += studentToAdd + "<br/>";
}

我还建议在循环之前添加此代码以生成新学生，而不是将其添加到上一组，以防用户多次单击该按钮

randomStudents = [];

数组中的名称列表，如何永远不会获得重复值

2 个答案: