JavaScript: Combine the numbers of a given array into an array containing all combinations
JavaScript fundamental (ES6 Syntax): Exercise-9 with Solution
Write a JavaScript program to combine the numbers of a given array into an array containing all combinations.
- Use Array.prototype.reduce() combined with Array.prototype.map() to iterate over elements and combine into an array containing all combinations.
Sample Solution:
JavaScript Code:
//#Source https://bit.ly/2neWfJ2
// Define a function called `powerset` that takes an array `arr`.
const powerset = arr =>
// Reduce the array to generate the powerset.
arr.reduce(
// For each element in the array, concatenate it with each element of the accumulated result.
(a, v) => a.concat(a.map(r => [v].concat(r))),
[[]]
);
// Test cases
console.log(powerset([1, 2]));
console.log(powerset([1, 2, 3]));
console.log(powerset([1, 2, 3, 4]));
Output:
[[],[1],[2],[2,1]] [[],[1],[2],[2,1],[3],[3,1],[3,2],[3,2,1]] [[],[1],[2],[2,1],[3],[3,1],[3,2],[3,2,1],[4],[4,1],[4,2],[4,2,1],[4,3],[4,3,1],[4,3,2],[4,3,2,1]]
Visual Presentation:
Flowchart:
Live Demo:
See the Pen javascript-basic-exercise-1-9 by w3resource (@w3resource) on CodePen.
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Previous: Write a JavaScript program to filter out the specified values from an specified array. Return the original array without the filtered values.
Next: Write a JavaScript program to extract out the values at the specified indexes from an specified array.
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