Every Other Element

Question

Every Other Element

I'm currently stuck on a math problem and could use some help. The task is to write a JavaScript function that identifies elements at even positions in an array. The array is composed of number elements. The desired result should be displayed in an element identified by the ID "result" as a text or string format. Here's an example: Input: [1, 2, 3, 4, 5, 6, 7, 8, 9] Output: 1 x 3 x 5 x 7 x 9 Below is the code I've written so far:

function evenPosition(arr) {

    let evenIndexes = [];
    let oddIndexes = [];

    for (let i = 1; i < arr.length + 1; i++) { 

        if (i % 2 !== 0) {
            oddIndexes.push(i)
        } else {
            evenIndexes.push(i)
        }

    }

}
evenPosition([1, 2, 3, 4, 5, 6, 7, 8, 9])

I'm having trouble getting the output in the desired format. If anyone could provide some guidance, I'd greatly appreciate it!

javascript arrays sorting

Answer 1

Answer №1

Do you desire this?

function alternateElements(array) {
 
    let result = "";
    for (let j = 0; j < array.length; j++) { 

        if (j % 2 !== 0) { 
            result += " x ";
        } else { 
            result += array[j];
        }

    }
    return result;
}
console.log(alternateElements([1, 2, 3, 4, 5, 6, 7, 8, 9]))

Answer 2

Do you desire this?

function alternateElements(array) {
 
    let result = "";
    for (let j = 0; j < array.length; j++) { 

        if (j % 2 !== 0) { 
            result += " x ";
        } else { 
            result += array[j];
        }

    }
    return result;
}
console.log(alternateElements([1, 2, 3, 4, 5, 6, 7, 8, 9]))

Answer 3

Answer №2

The provided example is incorrect according to the original post. In the array [1, 2, 3, 4, 5, 6, 7, 8, 9], the odd values are located at even indexes and the even values are located at odd indexes. Therefore, replacing the values at even indexes would result in "x 2 x 4 x 6 x 8 x".

There are numerous approaches to achieve this desired outcome, such as the following:

// Function to replace values at even indexes with "x" in a string
function evenPosition(arr) {
  let acc = 'x';
  return arr.slice(-(arr.length - 1)).reduce(
    (acc, curr, i) => acc += ' ' + (i%2? 'x' : curr), acc
  );
}

// Since indexes start at 0, even numbers are found at odd indexes
let a = [1,2,3,4,5,6,7,8,9];

console.log('Input: ' + a + ' Output: ' + evenPosition(a));

// Sparse array with ellisions
let b = [1,,,,5,6,,,9,10];

console.log('Input: ' + b + ' Output: ' + evenPosition(b));

// Utilizing map and join
console.log('Input: ' + a + 
            ' Output: ' + (a.map((v, i) => i%2? v : 'x').join(' ')));

Answer 4

The provided example is incorrect according to the original post. In the array [1, 2, 3, 4, 5, 6, 7, 8, 9], the odd values are located at even indexes and the even values are located at odd indexes. Therefore, replacing the values at even indexes would result in "x 2 x 4 x 6 x 8 x".

There are numerous approaches to achieve this desired outcome, such as the following:

// Function to replace values at even indexes with "x" in a string
function evenPosition(arr) {
  let acc = 'x';
  return arr.slice(-(arr.length - 1)).reduce(
    (acc, curr, i) => acc += ' ' + (i%2? 'x' : curr), acc
  );
}

// Since indexes start at 0, even numbers are found at odd indexes
let a = [1,2,3,4,5,6,7,8,9];

console.log('Input: ' + a + ' Output: ' + evenPosition(a));

// Sparse array with ellisions
let b = [1,,,,5,6,,,9,10];

console.log('Input: ' + b + ' Output: ' + evenPosition(b));

// Utilizing map and join
console.log('Input: ' + a + 
            ' Output: ' + (a.map((v, i) => i%2? v : 'x').join(' ')));

Answer 5

Answer №3

To convert an array into a string with specific characters separating the elements, you can utilize the array's join method. Here is an example of how to achieve this:

function getEvenPositionElements(arr) {

    let evenArr = [];
    for (let i = 0; i < arr.length; i++) { 

        if (i % 2 === 0) { 
            evenArr.push(arr[i]);
        }

    }
    return evenArr.join(" x ");
}
console.log(getEvenPositionElements([1, 2, 3, 4, 5, 6, 7, 8, 9]))

If you also want to sort the array before joining the elements, you can modify the function to return something like this:

return evenArr.sort().join(" x ");

Answer 6

To convert an array into a string with specific characters separating the elements, you can utilize the array's join method. Here is an example of how to achieve this:

function getEvenPositionElements(arr) {

    let evenArr = [];
    for (let i = 0; i < arr.length; i++) { 

        if (i % 2 === 0) { 
            evenArr.push(arr[i]);
        }

    }
    return evenArr.join(" x ");
}
console.log(getEvenPositionElements([1, 2, 3, 4, 5, 6, 7, 8, 9]))

If you also want to sort the array before joining the elements, you can modify the function to return something like this:

return evenArr.sort().join(" x ");

Every Other Element

Answer №1

Answer №2

Answer №3

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