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JavaScript

Posted by Daniel Hunter
Daniel Hunter
7,349 Points

Javascript Methods 2 - Task 2

Sort the 'saying2' array, on about line 19, so that the words are listed in length order. The shortest first. Use the 'length' property on the strings in the sort function.

<script>
      var saying1 = ["The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"];
      var saying2 = ["The", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog's", "back"];
      saying1.reverse();
      saying2.sort(function ());

I've got this one started, just not sure how to include the .length part.

3 Answers

Peter Szerzo
Peter Szerzo
22,661 Points

Hey Daniel,

Have a look at this code, which should answer your question:

saying2.sort( function(a, b) { return (a.length - b.length); });

What you are specifying in the parenthesis is the 'rule' which your program should follow when comparing two elements in your array - based on whether the return value is positive or negative. How does a comparison come into play? Sorting is very closely related to comparing. The sorting mechanism that is built into JavaScript swaps around elements in your array if they are in the wrong order, that is, if they don't compare as they should (if there is a longer string before a shorter one).

Let me know if you'd like further clarification.

Peter

Daniel Hunter
Daniel Hunter
7,349 Points

Ok great thanks!

geoffrey
geoffrey
28,736 Points
geoffrey
geoffrey
28,736 Points

Try this

var saying2 = ["The", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog's", "back"];

saying2.sort(function(a,b){ 
    return a.length -b.length; 
});

// this returns ["The", "fox", "the", "over", "lazy", "back", "quick", "brown", "dog's", "jumped"]

I coudln't remember the answser, so I checked the mozilla developer network to find the right answser.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort

Daniel Hunter
Daniel Hunter
7,349 Points

Thanks for sending this website, super helpful!

Brian van Vlymen
Brian van Vlymen
12,637 Points
Brian van Vlymen
Brian van Vlymen
12,637 Points

Hello, @Peter Szerzo, @geoffrey

Can you please explained to me better example please. One mostly I dont really understand why should we put "return a - b" however I completely understand ASCII or Unicode how the sort or length method work. let don't worry about the "length" method.

var saying2= [5,4,3,2,1,0]
If saying2.sort(function(a, b){
   return a - b;
}); 
console.log (saying2);

the answer would be 0,1,2,3,4,5 because of return is less than 0, sort a to a lower index than b, i.e. a comes first?

I am confused why required put "a - b" to make it work?

Brian van Vlymen
Brian van Vlymen
12,637 Points

Peter Szerzo geoffrey

Peter Szerzo
Peter Szerzo
22,661 Points

If a is lower than b, than (a - b) is negative, and this is "negativity" is what JavaScript needs to know. Think of it as translation between human languages: just suppose for a moment that within the sort method, "a is lower than b" is a phrase in Japanese and "a - b is negative" is a phrase in German. In this case, from the way it is implemented, JavaScript only speaks German.

That said, Chrome will let you sort by returning a true or false value in the function, but in that case, Safari will sort the other way (or at least the latest versions at that time). Not the most predictable behavior..