'In JavaScript, how can I update each element of an array the same way without using a loop?

For example, if I have an array:

movies = ["Spider Man", "Avatar", "Titantic", "Avengers"]

How do I turn the movies array into

[{title: "Spider Man"}, {title: "Avatar"}, {title: "Titantic"}, {title:"Avengers"}]

without using a loop? Is it possible to do it in O(1)?

In the same way, If I have an integer array and need to increment every element by one, can I do it without a loop?

javascriptalgorithmloops


Solution 1:[1]

It is impossible.

If your input set contains N elements, you cannot create a different structure of N other elements without a loop. Any algorithm that isn't hard-coded to the input array will require an O(n) loop.

The only (cheating) O(1) approach would be something like

const transformMovies = () => [{title: "Spider Man"}, {title: "Avatar"}, {title: "Titantic"}, {title:"Avengers"}];

which of course only works for one possible input, and not for the general problem.

Solution 2:[2]

I would suggest regex, open to discussion on the complexity of the process

const movies = ["Spider Man", "Avatar", "Titantic", "Avengers"]

let moviesStr = JSON.stringify(movies); // O(1)

moviesStr = moviesStr.replace('["', '[{"title":"') // O(1)
moviesStr = moviesStr.replace('"]', '"}]') // O(1)
const regex = /,"/ig;

moviesStr = moviesStr.replaceAll(regex, '},{"title":"') // O(1) ???

const updateObj =  JSON.parse(moviesStr);

console.log(updateObj)

Sources

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Source: Stack Overflow

Solution Source
Solution 1 CertainPerformance
Solution 2 Dipak

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