Find out the longest word from a sentence - Javascript

Question

Is there any way to find out the longest word in Javascript? It should ignore punctuation marks too!

I understood the logic, but the code... sigh

Here's what we do -

1. Count the number of alphanumeric characters that are together, not separated by a space or any sign.

2. Get their lengths.

3. Find the biggest length in all.
4. Return the word with the biggest length.

Hope I'm making myself clear...

Answer 1

Split the string, loop over the parts and keep track of the longest one.

Something like this:

var parts = sentence.split();
var longestIndex = -1;
var longestWord = 0;

for(var i=0; i < parts.length; i++){
    if(parts[i].length > longestWord){
        longestWord = parts[i].length;
        longestIndex = i;
    }
}

alert("longest word is " + parts[longestIndex] + ": " + longestWord + " characters");

If you need to split on non alphabetic characters as well as spaces you need to use regexes. You can change this line:

var parts = sentence.split();

To this (thanks Kooilnc for the regex):

var parts = sentence.match(/\w[a-z]{0,}/gi);

Working jsfiddle

Answer 2

var longest_word = arr.reduce(function (x, y) { return x.length > y.length ? x : y; });

There you go.

Using it:

var arr = [ 'lol', 'loll', 'lollll', 'lo', 'l' ];
var longest_word = arr.reduce(function (x, y) { return x.length > y.length ? x : y; });

So turn your sentence into an array, then the variable longest_word will be the longest word in that array.

Answer 3

try this:

sentence_array = sentence.split(' ');
var longest = sentence_array.sort(function (a, b) { return b.length - a.length; })[0];

Answer 4

You can split a string to an array of words only (no sepators, digits etc) using the match method, and sort that descending on length of each element, after which element 0 is the longest word.

It could be a String.prototype extension

String.prototype.longestWord = function(){
  return (this.match(/\w[a-z]{0,}/gi) || [''])
          .sort(function(a,b){return b.length-a.length;})[0];
}
//usage
'We saw it ...! A lazy cat walking - or did we?'.longestWord(); //=> walking
'------------'.longestWord();                                   //=> ''
'---aa--b----'.longestWord();                                   //=> 'aa'

The same as a function, using Array.reduce

function longestWord(str){
   return (str.match(/\w[a-z]{0,}/gi) || [''])
           .reduce( function(a,b){return a.length>b.length ? a : b;} );
}

Fiddle here

Answer 5

This is how I attempted to solve the problem:

function LongestWord(sen) { 
    var wordArray = sen.match(/\w+/gi);
    var longest = 0; 
    var word = undefined; 
  for(var i = 0; i < wordArray.length; i++){
    if(wordArray[i].length > longest){
       word = wordArray[i];
      longest = word.length;
    }
  }

  return word; 

}