for learning purposes I want to get every second element of an array. I succeeded with a for loop:
const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
function filterEverySecond(arr) {
let everySecondEl = [];
for (let i = 0; i < arr.length; i += 2) {
everySecondEl.push(arr[i]);
}
return everySecondEl;
}
console.log({
numbers,
result: filterEverySecond(numbers)
});Now I want to achieve the same without a for loop, but by using array methods (forEach, filter, map or reduce). Can anyone recommend which method would be best here?
you can do it easily with filter
const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const filtered = numbers.filter((_, i) => i % 2 === 0)
console.log(filtered)you just filter out the elements that have a odd index
You can use filter and check if the index of the current array element is divisible by 2:
const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
console.log({
numbers,
result: numbers.filter((_, index) => index % 2 === 0)
});You could use a for each loop like so to get the same desired output:
const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const result = [];
numbers.forEach(number => {
if (number % 2 != 0) {
result.push(number);
}
});
console.log(numbers);
console.log(result);The modulus operator returns the remainder of the two numbers when divided. For example: 1 % 2 will return 1 as the remainder. So in the if statement we are checking if the number is not divisible by 2.