Source address: https://juejin.im/post/5ae413946fb9a07a9c03f7f7
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<title>Document</title>
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<script>
class RandomSplit {
constructor(num) {
// actual total
this.num = this.getNum(num);
// gain
try {
this.multiple = this.num.toString().split('.')[1].length;
} catch (e) {
this.multiple = 0;
}
// total number for integer operations
this.calcNum = this.num * Math.pow(10, this.multiple);
}
// Determine whether it is a number (take "is-number")
isNumber(num) {
let number = +num;
if ((number - number) !== 0) {
return false;
}
if (number === num) {
return true;
}
if (typeof num === 'string') {
if (number === 0 && num.trim() === '') {
return false;
}
return true;
}
return false;
}
// get the number
getNum(num, defaultNum = 0) {
return this.isNumber(num) ? (+num) : defaultNum;
}
//The number of equal shares, the accuracy of the equal share, whether to directly return the enlarged integer
average(n, precision, isInt) {
precision = Math.floor(this.getNum(precision, 0));
n = Math.floor(this.getNum(n));
let calcNum = this.calcNum * Math.pow(10, precision < 0 ? 0 : precision);
// The number of copies exceeds the calculated total number after magnification, that is, the case of insufficient points
if (n > calcNum) {
return [];
} else {
let index = 0;
// average
let avg = Math.floor(calcNum / n);
// remainder
let rest = calcNum % n;
// remaining number fill interval
let gap = Math.round((n - rest) / rest) + 1;
// original average array
let result = Array(n).fill(avg);
//
while (rest > 0) {
index = (--rest) * gap;
result[index >= n ? (n - 1) : index]++;
}
// return the zoomed result array
if (isInt) {
return result;
}
// Return the result array that meets the precision requirements after processing
return result.map((item) => {
return (item / Math.pow(10, this.multiple + precision));
});
}
}
// The number of random divisions, the division accuracy
split(n, precision) {
n = Math.floor(this.getNum(n));
precision = Math.floor(this.getNum(precision, 0));
// evenly
let arr = this.average(n, precision, true);
let arrResult = arr.concat();
for (let i = 0; i < arr.length; i++) {
//total amount given
let num = Math.floor(Math.random() * arr[i]);
// Amount to give to left neighbor
let numLeft = Math.floor(Math.random() * num);
// Amount to give to right neighbor
let numRight = num - numLeft;
// First and last index processing
let iLeft = i === 0 ? (arr.length - 1) : (i - 1);
let iRight = i === (arr.length - 1) ? 0 : (i + 1);
arrResult[i] -= num;
arrResult[iLeft] += numLeft;
arrResult[iRight] += numRight;
}
// shrink to original size
return arrResult.map((item) => {
return (item / Math.pow(10, this.multiple + precision));
});
}
}
var r = new RandomSplit (250);
console.log(r.average(3))
console.log(r.split(3))
</script>
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