Search in multidimensional array (Algorithm)

Question

The Question

Write a function that gets a sequence and value and returns true/false depending on whether the variable exists in a multidimensional sequence.

Example:

locate(['a','b',['c','d',['e']]],'e'); // should return true
locate(['a','b',['c','d',['e']]],'a'); // should return true
locate(['a','b',['c','d',['e']]],'f'); // should return false

My Solution Seems To Work, but Code Wars says: "arr.flat is not a function.

I use the free code camp browser to run and test my code, and my console logs suggested I had it working, but Code Wars was saying arr.flat is not a function. Here is my code:

var locate = function(arr, value){
  let count = 0;
  arr.flat().map((item)=>{
    value == item ? count++ : count;
  });

  return count > 0 ? true : false;
}

My Question

Is my code correct or not? If not, what's wrong. If so, why might Code Wars be throwing an error?

Array.prototype.flat() isn't yet widely supported, maybe Code Wars doesn't support it either? You could still use one of the alternatives MDN proposes. — sp00m
– sp00m, Commented Jun 16, 2020 at 20:23

Robin Zigmond · Accepted Answer · 2020-06-18 08:09:50Z

1

You don't actually need .flat for this (although that would allow the most elegant solution of const locate = (arr, value) => arr.flat().includes(value);). Here's a simple recursive solution using an ordinary for loop:

const locate = function(arr, value) {
  for(let i = 0; i < arr.length; i++) {
    if (Array.isArray(arr[i]) {
      if (locate(arr[i], value) {
        return true;
      } 
    }
    if (arr[i] === value) {
      return true;
    } 
  }
  return false;
}

edited Jun 18, 2020 at 8:09

answered Jun 16, 2020 at 20:34

Robin Zigmond

18.3k2 gold badges25 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

ABGR · Accepted Answer · 2020-06-16 20:24:21Z

1

It seems to be working here. So chances are the browser on which you're testing doesn't support flat()

var locate = function(arr, value){
  let count = 0;
  arr.flat().map((item)=>{
    value == item ? count++ : count;
  });
  return count > 0 ? true : false;
}

console.log(locate(['a','b',['c','d',['e']]],'e')); // should return true
console.log(locate(['a','b',['c','d',['e']]],'a')); // should return true
console.log(locate(['a','b',['c','d',['e']]],'f')); // should return false

answered Jun 16, 2020 at 20:24

ABGR

5,2634 gold badges34 silver badges56 bronze badges

Comments

Nina Scholz · Accepted Answer · 2020-06-16 20:30:56Z

1

You could take a recursive approach with a short circuit on find.

function locate(array, value) {
    return array.some(v => Array.isArray(v) && locate(v, value) || v === value);
}

console.log(locate(['a', 'b', ['c', 'd', ['e']]], 'e')); // true
console.log(locate(['a', 'b', ['c', 'd', ['e']]], 'a')); // true
console.log(locate(['a', 'b', ['c', 'd', ['e']]], 'f')); // false

answered Jun 16, 2020 at 20:30

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Comments

Siva Kondapi Venkata · Accepted Answer · 2020-06-17 05:12:38Z

1

Since flat is supported in your environment, Write own flat method and use the includes

const flat = (arr, res = []) => (
  arr.forEach((item) =>
    Array.isArray(item) ? flat(item, res) : res.push(item)
  ),
  res
);

const locate = (arr, value) => flat(arr).includes(value);

console.log(locate(["a", "b", ["c", "d", ["e"]]], "e"));
console.log(locate(["a", "b", ["c", "d", ["e"]]], "a"));
console.log(locate(["a", "b", ["c", "d", ["e"]]], "f"));

answered Jun 17, 2020 at 5:12

Siva Kondapi Venkata

11.1k2 gold badges20 silver badges32 bronze badges

Collectives™ on Stack Overflow

Search in multidimensional array (Algorithm)

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related