javascript - 用带条件的数字升序填充数组

Question

如何使用以下条件用数字的升序填充数组：

• 数组中的第一个元素是let a = 0;

• 数组元素之和等于var sum = 10;

• 数组的长度应该是var length = 10;

这是我创建的代码：

    var length = 10;
    var array = []; 
    var sum = 10; // the sum of all elements in the array should be equal to this
        
    for (let i = 0; i < length; i++) {
        let a = 0; // the very first element of array
        // Math equations
        let last = (sum - (length / 2 * a)) * 2 / length
        let dd = (last - a) / (length - 1)
    
        sume = (dd * (i));
        array.push(sume);
    
    }

    // check to see if array elemements sum is equal to "var sum = 10"
    let reducer = (accumulator, currentValue) => accumulator + currentValue;
    let sumArray = array.reduce(reducer);
    console.log("sumArray: " + sumArray)
    
    console.log(array) // results

但问题不是像这样有整数（它仍然符合我的所有条件）：

[0, 0, 0, 0, 1, 1, 1, 2, 2, 3]

但我得到了这些结果：

[0, 0.2222222222222222, 0.4444444444444444, 0.6666666666666666, 0.8888888888888888, 1.1111111111111112, 1.3333333333333333, 1.5555555555555554, 1.7777777777777777, 2]

注意：我在这里计算了最后一项：let last = (sum - length / 2 * a) * 2 / length第一项始终为 0...

标签： javascript

Answer 1

您可以对值进行四舍五入。

sume = Math.round(dd * i);

    var length = 10;
    var array = []; 
    var sum = 10; // the sum of all elements in the array should be equal to this
        
    for (let i = 0; i < length; i++) {
        let a = 0; // the very first element of array
        // Math equations
        let last = (sum - length / 2 * a) * 2 / length
        let dd = (last - a) / (length - 1)
    
        sume = Math.round(dd * i);
        array.push(sume);
    
    }

    // check to see if array elemements sum is equal to "var sum = 10"
    let reducer = (accumulator, currentValue) => accumulator + currentValue;
    let sumArray = array.reduce(reducer);
    console.log("sumArray: " + sumArray)
    
    console.log(array) // results

一种更短的舍入方法（它可能不适用于所有情况）。

const add = (a, b) => a + b;

function disperse(length, sum) {
    var min = 0,
        max = sum * 2 / length,
        array = Array.from({ length }, (_, i) => Math.round(min + i * max / (length - 1)));
    return [array.reduce(add), array.join(', ')];
}

console.log(disperse(10, 10));
console.log(disperse(10, 30));
console.log(disperse(20, 50));

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