Largest Array issue

[aznoh]

Me again haha. I would love to know why my console.log is coming out with just [4, 5]

I know I’m a long shot away from completing the challenge but would like to understand the [4, 5] part. Many thanks guys.

   **Your code so far**

function largestOfFour(arr) {
let longestNumber = [];
for(let i = 0; i < arr.length; i++){
  for (let j = 0; j < arr[i].length; j++){
if (arr[i][j] > longestNumber){
  longestNumber.push(arr[i][j])
}
  }
}
 
   console.log(longestNumber)
   
 return longestNumber;
}

largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);

   **Your browser information:**

User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.109 Safari/537.36

Challenge: Return Largest Numbers in Arrays

Link to the challenge:

freeCodeCamp.org

[lbrod]

My guess would be that once your array longestNumber has two values in it, no individual element in a sub-array (arr[i][j]) is going to be considered bigger than that.

I created a function to test this out myself (where arr_one has one value and arr_two has two:

function question(arr_one, arr_two){

if (arr_one > arr_two){

return true;

} else {

return false;

}}

And that’s how it seems if you compare, say, [1000] to [4,5]. Weirdly if the first value in array_two is 1 or less, it says it is bigger, which makes no sense to me, but I don’t think that will be an issue with this problem.

[snowmonkey]

This is close. While the array is a single value, or even no value, the > comparison is using the numeric coercion: Number([]) === 0 and Number([4]) === 4.

But when we get to [4, 5], then the Number coercion breaks down: Number([4,5]) === NaN. And the > comparison silently fails.

@aznoh, I’ll give you the same advice I just gave on another topic: when facing a challenge like this one that might take a little more work, I’ll pull them into a replit (https://replit.com/) and play around with different ideas. see what works and what doesn’t.

I’ll add console.log() things in there, get a look at variables inside the loops, and see what’s really going on.

Further, I’d take a little time and think about what is meant by “largest of four” here. What you’re currently doing is, if the value in longestNumber is less than the one you’re comparing to, you’re pushing another number onto longestNumber. By that approach, you’ll end up with all sixteen numbers in.

Instead, make a plan. When you first get into that outer loop (your i loop), you know something about the first value in that nested array. What do you explicitly know about 4 in that first array, or 13 in the second one, 32 in the third, and 1000 in the fourth?

[aznoh]

Thank you so much. This has really helped me.