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JavaScript: Get every nth element in a given array

JavaScript fundamental (ES6 Syntax): Exercise-21 with Solution

Write a JavaScript program to get every nth element in a given array.

  • Use Array.prototype.filter() to create a new array that contains every nth element of a given array.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const every_nth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1);
console.log(every_nth([1, 2, 3, 4, 5, 6], 1));
console.log(every_nth([1, 2, 3, 4, 5, 6], 2));
console.log(every_nth([1, 2, 3, 4, 5, 6], 3));
console.log(every_nth([1, 2, 3, 4, 5, 6], 4));

Sample Output:

[1,2,3,4,5,6]
[2,4,6]
[3,6]
[4]

Pictorial Presentation:

JavaScript Fundamental: Get every n<sup>th</sup> element in a given array
JavaScript Fundamental: Get every n<sup>th</sup> element in a given array

Flowchart:

flowchart: Get every nth element in a given array

Live Demo:

See the Pen javascript-basic-exercise-1-21 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

Returns an array of n-tuples of consecutive elements

Example:

const tips_arr = (n, arr) =>  n > arr.length ? [] : arr.slice(n - 1).map((v, i) =>[...arr.slice(i, i + n - 1), v]);
console.log(tips_arr(2, [1, 2, 3, 4, 5])); 
console.log(tips_arr(3, [1, 2, 3, 4, 5]));
console.log(tips_arr(5, [1, 2, 3, 4]));

Output:

[[1, 2], [2, 3], [3, 4], [4, 5]]
[[1, 2, 3], [2, 3, 4], [3, 4, 5]]
[]