javascript - loop through array, returns odd and even numbers - Stack Overflow

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I am teaching myself code and am trying to solve this problem:

Write a loop that loops through nums, if the item is even, it adds it to the evens array, if the item is odd, it adds it to the odds array.

This is what I have so far:

var nums = [1,2,34,54,55,34,32,11,19,17,54,66,13];
var evens = [];
var odds = [];

var evenNumbers = function(nums) {
    for (var i = 0; i < nums.length; i++) {

        if ((nums[i] % 2) != 1) {
            evens.push(nums[i]);
                console.log(evens);
        }
        else {
            odds.push(nums[i]);
                console.log(odds);
        }
    }

};

alert(evens);
alert(odds);

They don't return anything and I'm not sure where I'm going wrong, any help would be much appreciated.

I am teaching myself code and am trying to solve this problem:

Write a loop that loops through nums, if the item is even, it adds it to the evens array, if the item is odd, it adds it to the odds array.

This is what I have so far:

var nums = [1,2,34,54,55,34,32,11,19,17,54,66,13];
var evens = [];
var odds = [];

var evenNumbers = function(nums) {
    for (var i = 0; i < nums.length; i++) {

        if ((nums[i] % 2) != 1) {
            evens.push(nums[i]);
                console.log(evens);
        }
        else {
            odds.push(nums[i]);
                console.log(odds);
        }
    }

};

alert(evens);
alert(odds);

They don't return anything and I'm not sure where I'm going wrong, any help would be much appreciated.

• javascript
• loops

Share Improve this question Follow edited Nov 12, 2014 at 21:03 Barmar 781k5656 gold badges545545 silver badges659659 bronze badges asked Nov 12, 2014 at 21:01 TraceTrace 6711 gold badge22 silver badges66 bronze badges 1

• 5 You never call the function. – Barmar Commented Nov 12, 2014 at 21:03

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9 Answers 9

Sorted by: Reset to default 11

I would recommend checking out the array.prototype.filter function with ES6 syntax:

const oddNumbers = [1,2,34,54,55,34,32,11,19,17,54,66,13].filter((number) => number%2!==0);
console.log(oddNumbers);

So elegant :)

You're not actually executing the function. You need to call evenNumbers();

var nums = [1,2,34,54,55,34,32,11,19,17,54,66,13];
var evens = [];
var odds = [];

var evenNumbers = function(nums) {
    for (var i = 0; i < nums.length; i++) {

        if ((nums[i] % 2) != 1) {
            evens.push(nums[i]);
                console.log(evens);
        }
        else {
            odds.push(nums[i]);
                console.log(odds);
        }
    }

};

evenNumbers(nums);
alert(evens);
alert(odds);

You aren't actually calling your function, just defining it.

call:

evenNumbers(nums);

before alerting the arrays

function groupNumbers(arr) {

  var arr = [1,2,3,4,5,6,7,8,9,10];

  var evenNumbers = arr.filter(number => number % 2 == 0);

  console.log("Even numbers " + evenNumbers);

  var oddNumbers = arr.filter(number => number % 2 !== 0);

  console.log("Odd numbers " + oddNumbers);
}

groupNumbers();

var rsl = {even:[], odd:[]};

[1,2,34,54,55,34,32,11,19,17,54,66,13].forEach(function(val,key,arr)
{
    var wrd = (val % 2) ? 'odd' : 'even';
    rsl[wrd][rsl[wrd].length] = val;
});

console.log(rsl);

            //Even odd
            var arrays = [1,2,34,54,55,34,32,11,19,17,54,66,13];
            var result = arrays.filter((numbers)=>{
                 if(numbers%2!==0){
                   console.log(`${numbers} is not even`);
                 } else {
                     console.log(`${numbers} is even`);
                }
            });

Here is a snippet :

const arr = [24,42,543,676,456,535,555];
console.log("Values: "+arr);
var even = arr.filter((number)=>number%2 === 0);
console.log("Even Number: "+even);
var odd = arr.filter((number)=>number % 2 !==0);
console.log("Odd Number: "+odd);

Someone can try according to the way:

function findOddEven(arr){
    let odd=[],even=[],i=0,j=0,k=0;
    for(i;i<arr.length;i++){
        if(arr[i]%2==0){
          even[j++]=arr[i]
        }else{
            odd[k++]=arr[i]
        }
    }
    console.log("Even and Odd number",even,odd)
}

findOddEven([2,13,4,26,17])

function sortEvenOdd(arr, arrSize) {
  let odd = [];
  let even = [];
  for (let i = arrSize - 1; i >= 0; i--) {
    if (arr[i] % 2 !== 0) {
      odd.push(arr[i]);
    } else {
      even.push(arr[i]);
    }
  }
  even.sort(function (a, b) {
    return a - b;
  });
  odd.sort(function (a, b) {
    return b - a;
  });

  return [...odd, ...even];
}

// return odd and even numbers
/* Sample Input
7
1 2 3 5 4 7 10

Sample Output 7 5 3 1 2 4 10

Sample Input
7
0 4 5 3 7 2 1

Sample Output 7 5 3 1 0 2 4 */

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