CODEWITHSUNDEEP
javascriptarraysalgorithm
AndrewNeedsHelp
AndrewNeedsHelp

Reputation: 415

Search in multidimensional array (Algorithm)

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?

Upvotes: 1

Views: 470

Answers (4)

Robin Zigmond
Robin Zigmond

Reputation: 18249

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;
}

Upvotes: 1

Siva Kondapi Venkata
Siva Kondapi Venkata

Reputation: 11001

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"));

Upvotes: 1

Nina Scholz
Nina Scholz

Reputation: 386550

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

Upvotes: 1

ABGR
ABGR

Reputation: 5205

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

Upvotes: 1

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