Javascript .split

Question

This question may seem a little silly, but i just need to know. So here is some very basic code i wrote:

function LongestWord(sen) { 
  var longest = "";
  var check = ""; //I've even changes the value of var check into a integer and still returned the same

  for(var i = 0; i < sen.length; i++){
    check = sen.split(" ");
  }

  return check;              
}

console.log(LongestWord("John Max"));

This is what is returned: [ 'John', 'Max' ]

Does this mean that when the .split() method is called on a variable, it converts it into an Array no matter which type it is?

Not sure what you mean by "no matter which type it is", but you may want to check out some of the documentation. Oh, and since check is returned, only the last value in your for loop will be returned. — user1932079
– user1932079, Commented Aug 4, 2014 at 5:29
check gets assigned the result of sen.split(), so it becomes an array when you do that. — Ja͢ck
– Ja͢ck, Commented Aug 4, 2014 at 5:30
[var] automatically adjust its data type depending on the assigned value. — Saechel
– Saechel, Commented Aug 4, 2014 at 5:31
The previous value of a variable imposes no limitations on the values you can assign to it. You can do check = 3; check = []; check = new Date();, and each assignment will replace the old value, ignoring the old value's type entirely. — user2357112
– user2357112, Commented Aug 4, 2014 at 5:37

Ja͢ck · Accepted Answer · 2014-08-04 05:37:45Z

1

Variables in JavaScript are dynamic; this means that they can change type during the execution of your script.

For example:

var a = 123; // i'm a number value

a = []; // now i'm an array

a = 'hello'; // and now i'm a string

Any previous value is discarded (*) when a new value is assigned to it.

That said, the logic in your script can be written like this:

var longest = null;

sen.split(' ').forEach(function(word) {
    if (longest === null || word.length > longest.length) {
        longest = word;
    }
});

return longest;

(*) garbage collection behaviour is different between scalars and non-scalars.

answered Aug 4, 2014 at 5:37

Ja͢ck

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Comments

Ende Neu · Accepted Answer · 2014-08-04 05:30:39Z

1

No, split() is a method defined on strings in Javascript and it returns an array with the splitted words

"hello, world".split(",") // returns [hello, world]

So you can't use it on every object type.

answered Aug 4, 2014 at 5:30

Ende Neu

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Jonathan · Accepted Answer · 2014-08-04 05:30:59Z

0

split is a function on the String prototype. It will only work on a string.

It splits the value of the string based on the provided delimiter, then returns an array of the 'pieces' of the original string.

Here is the doc page: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split

answered Aug 4, 2014 at 5:30

Jonathan

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Mritunjay · Accepted Answer · 2014-08-04 05:31:10Z

0

Yes, Split returns an array of strings separated by specified delimiter.

.split is a String method so you cannot call it on other types.

answered Aug 4, 2014 at 5:31

Mritunjay

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Comments

phoenixdown · Accepted Answer · 2014-08-04 05:36:36Z

Yes if you're calling it on a String. "The split() method splits a String object into an array of strings by separating the string into substrings."

To be precise, .split() is a String method, so it works on String objects. As stated, it converts the string into an array of strings separated by the separator value passed to .split(). If an empty string is passed as the separator value, an array of characters comprising the original string is returned.

See also: "Note: When the string is empty, split returns an array containing one empty string, rather than an empty array."

The answers claiming you cannot call it on non-String objects are correct. Calling it on a non-String object results in Uncaught TypeError: undefined is not a function.

For example:

var name = "234";
var newName = name.split("3");
console.log(newName);

This returns ["2","4"]

var name = 234;
var newName = name.split("3");
console.log(newName);

Returns the TypeError above.

If you insist on using .split() on a non-String object, you can call it using .call() to access the .split() method via prototypal inheritance as follows.

var name = 234;
var newName = String.prototype.split.call(name, "3");
console.log(newName);

This prints ["2","4"] to the console.

khizerbajwa · Accepted Answer · 2014-08-04 06:31:44Z

Not sure what you are trying to ask, but as Jeremy has pointed out, the split() function returns an array of all substrings formed after splitting the original string for the given separator. You can then parse this array of substrings, checking their lengths and finding your longest word. The current loop you have is useless, as it does the same thing again and again which can be simply done in the single line

check = sen.split(" ");

Following is some sample code to split a string and find the longest word. Hope this solves your problem.

function LongestWord(sen) {
    var check = sen.split(" ");
    var lIndex = -1;
    var lWordLength = 0;

    for(var i=0; i < check.length; i++){
        if(check[i].length > lWordLength){
            lWordLength = check[i].length;
            lIndex = i;
        }
    }
    return check[lIndex]
}

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