let result = Math .random ()*(m+ 1 -n)+n; while (result>m){ result = Math .random ()*(m+ 1 -n)+n; return result; //取得(n,m)范围随机数 function fullOpen (n,m){ let result = Math .random ()*(m-n)+n; while (result == n){ result = Math .random ()*(m-n)+n; return result; //取得(n,m]范围随机数 function leftOpen (n,m){ let result = Math .random ()*(m-n+ 1 )+n- 1 ; while (result<n){ result = Math .random ()*(m-n+ 1 )+n- 1 ; return result;

4.生成随机整数

Math.round(num):四舍五入取整

Math.floor(num):将num向下取整,即返回num得整数部分。也可用parseInt()

//生成[0,n)范围内得随机整数
Math.floor(Math.random()*n)
//生成[nim,max]范围内得随机整数
Math.floor(Math.random()*(max-min+1))+min
//生成[1,n]范围内随机数
Math.floor(Math.random()*n)+1

5.随机字符串生成

//生成n位数字字符串
function randomNum(n){
    let res = ''
    for(let i=0;i<n;i++){
        res += Math.floor(Math.random()*10);
    return res;
//生成n位数字字母混合得字符串
function generateMixed(n){
    let chars = ['0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'];
    let res = '';
    for(let i=0;i<n;i++){
        let id = Math.floor(Math.random()*36);
        res += chars[id]
    return res;
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