JS Find the Longest Word in a String

Lean Rasmussen The poster explicitly states that they don't want a direct answer (solution) only a hint as to what to do. Your answer definitively provides more than that.

Also the challenge is to return the length of the longest word, not the longest word itself.

Edit: Thank you for editing your answer.

Hi Trevor,

Were you intending to sort the words by length? As you have it now, the default sort isn't going to help you and will only waste time because it sorts based on unicode point order. You would need to use a compare function to sort by length.

If you did do that then you wouldn't need to loop at all because the longest word would be at the end or the beginning depending on the sort order.

However, I recommend that you take the approach hinted at in the answers and not do any sorting because those approaches will be faster than sorting.

My loop seems to be checking the length of the first word in the array instead of looping through the whole thing and only adding to the length variable if the array item is longer than the variable. Am I returning too early?

function findLongestWord(str) {

  var length;
  var stringArray = [];
  var string = str;
  stringArray = string.split(' ');

  for (i = 0; i < stringArray.length; i++) {
    length = 0;
    if (stringArray[i].length > length) {
    length += stringArray[i].length;
    } 
    return length;
  }
}

findLongestWord("The quick brown fox jumped over the lazy dog");

Trevor Johnson: Yes, you are returning to early. Your return statement is placed within your for loop, which means that the function will always return after one loop.

That issues can be solved by simply moving it out of the loop. But it is far from the only issue in your current code. Your length variable should not be declared with it's initial value within the loop, but outside it. Declaring it within the loop means that it will be set to that value each time the loop runs, which means that it won't be useful for keeping track of the previous item's length.

There is another issue in your code but since you want to work on this yourself I'll limit my hints for the time being.

Thanks for your help guys, I solved it. I didn't know that placing that variable within the loop would reset it to zero each time.

Do any of you happen to know a more efficient way for doing this challenge than I did it? Something that would use less code?

Edit: renamed variable using camelcase.

In terms of efficiency, I don't know of anything. This solution is going to run in linear time. You have to go through the array and look at every single word.

If you had sorted it then it would probably run on average in n log(n) time.

There's a graph on the following big O wikipedia page https://en.wikipedia.org/wiki/Big_O_notation

If you look at the graph with the different time complexities, you'll see that n log(n) grows much faster than n

In terms of shorter code, you could handle the variable declarations part a little differently.

I would probably write it like this:

var maxLength = 0; // you can declare and initialize the max length in one step. I also renamed it to better indicate what it's storing.
var words = str.split(' '); // same thing here. the words can be declared and initialized in one step.

// then do the loop

Trevor Johnson: More efficient and less code is not always the same thing, your solution is actually pretty efficient performance wise. But as far as code length is concerned the shortest way I can think of to code this function is this:

function findLongestWord(str) {
  return str.split(' ').sort((a, b) => b.length - a.length)[0].length;
}

The more you try to shorten code the less readable it tends to become, especially to a beginner since it often involves using somewhat advanced functions and features. But in essence I'm just combining various operations into one line.

I first split the string then I call the sort method on that split string, then pass a function (arrow function) to the sort method which tells it how I want it to sort the array. The condition I provide will result in the array being sorted from longest word to shortest. Then I pull out the first item from the array and call the length method on that.