创建一个随机值并传递给数组

请尝试以下代码..

//For Search textbox random value
var myPlaceHolderArray = ['Hotels in New York...', 'Hotels in San Francisco...', 'Hotels Near Disney World...', 'Hotels in Atlanta...'];
var rand = Math.floor(Math.random() * myPlaceHolderArray.length);
var Placeholdervalue = myPlaceHolderArray[rand];

alert(Placeholdervalue);

最短的版本: var myArray = ['January'， 'February'， 'March']; var rand = myArray[(Math.random() * myArray.length) | 0] console.log (rand)

简单功能:

var myArray = ['January', 'February', 'March'];
function random(array) {
     return array[Math.floor(Math.random() * array.length)]
}
random(myArray);

OR

var myArray = ['January', 'February', 'March'];
function random() {
     return myArray[Math.floor(Math.random() * myArray.length)]
}
random();

OR

var myArray = ['January', 'February', 'March'];
function random() {
     return myArray[Math.floor(Math.random() * myArray.length)]
}
random();

如果你的项目中已经包含了下划线或lodash，你可以使用_.sample。

// will return one item randomly from the array
_.sample(['January', 'February', 'March']);

如果你需要随机获取一个以上的项，你可以将它作为第二个参数在下划线中传递:

// will return two items randomly from the array using underscore
_.sample(['January', 'February', 'March'], 2);

或者使用_。lodash中的sampleSize方法:

// will return two items randomly from the array using lodash
_.sampleSize(['January', 'February', 'March'], 2);

编辑Array原型可能有害。这里是一个简单的函数来完成这项工作。

function getArrayRandomElement (arr) {
  if (arr && arr.length) {
    return arr[Math.floor(Math.random() * arr.length)];
  }
  // The undefined will be returned if the empty array was passed
}

用法:

// Example 1
var item = getArrayRandomElement(['January', 'February', 'March']);

// Example 2
var myArray = ['January', 'February', 'March'];
var item = getArrayRandomElement(myArray);

~~比Math.Floor()快得多，所以当涉及到使用UI元素生成输出的性能优化时，~~赢得了比赛。更多信息

var rand = myArray[~~(Math.random() * myArray.length)];

但是，如果您知道数组将有数百万个元素，那么您可能需要在位操作符和Math.Floor()之间重新考虑，因为位操作符对大数字的表现很奇怪。请参阅下面的输出示例。

var number = Math.floor(14444323231.2); // => 14444323231
var number = 14444323231.2 | 0; // => 1559421343