javascript - 仅将最后一个值推送到数组

Question

我正在研究素数算法，我几乎完成了它。我认为每次循环完成时输出数组都会更新，所以如果我用素数调用函数:例如 primes(7) ，我得到 [7] 而不是 [2,3,5,7]。如果使用非素数调用，则输出 arr 为空。

这里是代码:

function rimes(num){
    var outputArr = [];

    for(var i=1; i<=num; i++){  
        function range(start, count) {
            return Array.apply(0, Array(count))
                    .map(function (element, index) { 
                             return index + start;  
                         });
        }
        var rangeArr = range(1,num);
        var current = i;

        function rangeFiltering(value){
            return value !== 1 && value < current;
        }
        var filteredRange = rangeArr.filter(rangeFiltering);

        function dividingByEachRangeElement(rangeElement){
          return current % rangeElement !== 0;
        }
        var divided = filteredRange.filter(dividingByEachRangeElement);

        if(divided.length === num - 2){  //current is prime if there are all numbers from 1 to current in divided array.(if there are zeros after modulo) i.e. when current is 5(prime), divided array is [2,3,4]. When current is 6(non prime), divided arr is [4,5] - 2,3 are missing because 6%2 = 0 and 6%3 = 0. 
            outputArr.push(current);
        }
    }
    console.log(outputArr);
}
sumPrimes(47);


//sumPrimes(6)  -> [];
//sumPrimes(7)  -> [7];
//sumPrimes(11) -> [11];

我该如何解决这个问题？

Answer 1

您的问题已上线:

if(divided.length === num - 2)

这意味着只有当divided的长度恰好等于num - 2时，当前数字才会被添加到outputArr，这仅在以下情况下为真:在您的示例中，i 或 current 等于 7。

将其更改为:

if(divided.length === current - 2)

应该可以解决问题。