用途
几乎模块中所有函数都依赖于基本函数random(),它在半开放范围[0.0,1.0)内产生一个统一的随机浮点数。
1.基本使用
var num = parseInt(Math.random() * 10);//取0到10之间的整数(但不包括10)
2.在指定范围内产生多个不同的随机数
var num = parseInt(Math.random() * 50 + 50) //取的是50到100之间的随机整数(不包括100)
3.从任意值开始至任意值
function fRandomBy(under, over){
switch(arguments.length){
case 1: return parseInt(Math.random() * under + 1);
case 2: return parseInt(Math.random() * (over - under + 1) + under);
default: return 0;
}
}
document.write(fRandomBy(100,300));//输出指定范围内的随机数的随机整数
4.随机生成5个五位数的整数,然后输出该数共有多少位,每位数分别是什么?
for ( var m = 0; m < 5 ; m++){
var arr = ["0","1","2","3","4","5","6","7","8","9"];
var obj = [];
var newArr = "";
for (var j = 0;j < 5; j++){
var index = parseInt(Math.random() * 10);
newArr += arr[index ];
}
for (var i = 0;i < newArr .length;i++){
obj[i] = parseInt(newArr[i]);
}
console.log("第" +( m + 1 )+"个数为" + newArr + ",共有" + newArr.length + "位数");
for (var k in obj){
console.log("第" + (parseInt(k) + 1) + "位为" + obj[k]);
}
newArr ="";
console.log("");
}