工具类-util.math

 1 /**
 2  * @description generate a random number
 3  * @author x.radish
 4  * @param {int} _minNum The min number
 5  * @param {int} _maxNum The max number
 6  * @param {Array} _rejArr reject array
 7  * @return {int} -1 error
 8  */
 9 function random(_minNum,_maxNum,_rejArr){
10     var minNum=_minNum||4,
11         maxNum=_maxNum||17,
12         rejArr=_rejArr||[],
13         num=-1,
14         flag=true;
15     num = Math.floor(Math.random()*(maxNum-minNum+1)+minNum);
16     if(rejArr.length>maxNum-minNum) return -1;
17     for(var i=0,len=rejArr.length;i<len;i++){
18         if(num==rejArr[i]){
19             flag=false; break;
20         }
21     }
22     if(flag) return num; else return random(minNum,maxNum,rejArr);
23 }

/**
 * @description Direct interception of the decimal without rounding
 * @author x.radish
 * @param {int} digits The number of decimal places
 * @return {Number}
 */
Number.prototype.toFix=function(digits){
    var f=parseInt(digits),
        n=Number(this),
        s=n.toString();
    var p=s.split(".");
    if(p[1]&&p[1].length>f){
        p[1]=p[1].substring(0,f);
        n=Number(p.join("."));
    }else{
        n=Number(this);
    }
    return n;
}