给定一组正数，负数和零数字，返回百分比数组

Question

I need some help with a problem which requires this:

We need a function FractionOf that receives an array and return another with the following three numbers:

 in the first position, the fraction of numbers that are positive
 in the second position, the fraction of numbers that are zero
 in the last position, the fraction of numbers that are negative

For example, FractionOf ([1, 2, 0, -1]) should return [0.5, 0.25, 0.25], given that there are 50% positive, 25% zero, and 25% negative.

So i tried to give at least some form to what they asked me, but i'm stuck on how to convert percentages to fractions and add them to the position.

var nums=[1,2,0,0,-1,-4]
function FractionOf(nums){
  var result=[]
  var num1=0
  var num2=0
  var num3=0
  for(var i=0; i<nums.length; i++){
    var num=nums[i]
    if(num>0){
      num1= num1 + 0.25}
    if (num==0){
      num2=num2 + 0.25}
    if(num<0){
     num3=num3 + 0.25}
result.push(num1)
result.push(num2)
result.push(num3)
return result
}

Answer 1

function FractionOf(nums) {
  return nums
    .reduce((acc, cur) => {
      if (cur > 0) acc[0]++;
      else if (cur === 0) acc[1]++;
      else acc[2]++;
      return acc;
    }, [0, 0, 0])
    .map(result => result / nums.length);
}

This solution uses reduce to count up the occurrences of each of the three cases, starting with an array filled with 0s. The result is piped to the map function, which divides each value by the length of the input num to obtain a percentage ranging from 0-1.

Answer 2

To get the results in percentages you should compute the fraction of a set with the formula:

( total_numbers_from_a_subset / total_numbers ) * 100.

try with:

var nums=[1,2,0,0,-1,-4]
function FractionOf(nums){
  var result=[]
  var num1=0
  var num2=0
  var num3=0
  for(var i=0; i<nums.length; i++){
    var num=nums[i]
    if(num>0){
      num1++; //how many numbers in the set are < 0
    }
    if (num==0){
      num2++
    }
    if(num<0){
     num3++
    }
}
result.push(num1 / nums.length * 100)
result.push(num2 / nums.length * 100)
result.push(num3 / nums.length * 100)
return result

Answer 3

you can get your desired result with this....

var nums=[6,5,0,-5,-3]
        function FractionOf(nums){
            var result = [];
            var positive = 0;
            var zero = 0;
            var negative = 0;
            for(var i = 0; i < nums.length; i++){
                if(nums[i] > 0){
                    positive++;
                }
                if (nums[i] == 0){
                    zero++;
                }
                if(nums[i] < 0){
                    negative++;
                }
            }
            result.push(positive / nums.length * 100);
            result.push(zero / nums.length * 100);
            result.push(negative / nums.length * 100);
            return result;
        }

hope this helps...

Answer 4

You could reduce the array by returning the sum foe every wanted check and map the parts of it.

 function fractionsOf(nums) { return nums .reduce(([p, m, n], v) => [p + (v > 0), m + (v < 0), n + (v === 0)], [0, 0, 0]) .map(v => v / nums.length); } console.log(fractionsOf([1, 2, 0, -1])); console.log(fractionsOf([1, 2, 0, 0, -1, -4]));