JavaScript - better approach to a problem of spliting an array

Question

The problem I have to solve is the following -

splitEven(a) – The function accepts an array of integers and would return an array that contains the values that are located in the even indices of the original array, sorted in ascending order. For example, if the function gets the array [3, 1, 6, 7, 4] it would return the array [3, 4, 6]

This is my solution -

    function splitEven(a){
    var b = [];
    var even = function(element){
        return element % 2 === 0;
    }
    for (var i = 0; i < a.length; i++) {
        var c = even(a[i]);
        if (c) {
            b.push(a[i])
        }
    }
    return b;
}

However I feel it is not best practice to do what I have done. I am familier with Java, and I think I tend to solve problems not in the right way.

Can you think of a better approach for this problem, to improve my practice?

CertainPerformance · Accepted Answer · 2018-12-18 09:03:08Z

6

You can use filter to create an array that contains only the even-numbered indicies in the original array, and then sort() that array:

const splitEven = arr => arr
  .filter((_, i) => i % 2 === 0)
  .sort((a, b) => a - b);

console.log(
  splitEven([3, 1, 6, 7, 4])
);
console.log(
  splitEven([3, 1, 6, 7, 4, 11, 12])
);

answered Dec 18, 2018 at 9:03

CertainPerformance

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Comments

Ivar · Accepted Answer · 2018-12-18 09:16:53Z

1

Another approach to simplify your code is to use an IF statement nested in your FOR loop.

function splitEven(array) {
  var even = [];

  for (let i = 0; i < array.length; i++) {
    if (array[i] % 2 == 0) {
      even.push(array[i]);
    }
  }
  return even;
}

edited Dec 18, 2018 at 9:16

Ivar

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answered Dec 18, 2018 at 9:15

jorgeRamirez

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2 Comments

Assaf Over a year ago

Thank you, indeed nicer.

Geshode Over a year ago

That checks, if the element of the array is even and not if the index is.

Geshode · Accepted Answer · 2018-12-18 09:35:47Z

1

You could just increase by 2 instead of 1 and in the end use sort().

function splitEven(array){
    var b = [];
    for (i = 0; i < array.length; i += 2){
      b.push(array[i]);
    }

    b.sort((a,b) => {return a-b;});

    return b;
}

answered Dec 18, 2018 at 9:35

Geshode

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