Code Challenge: Method 1: Ordering

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

Shea,

I, too, used the greater-than (>) operator at first, but after a little browsing this is what I came up with after checking out a description of the sort() function at Mozilla Developer Network.

If you were to use the greater-than (>) or the less-than (<) operators, then you would be returning a boolean value (true or false). By using the minus (-) operator, you are returning an integer, which is what a.length returns. The sort() function is then using that integer as a way to place the strings in ascending order by length.

For example, assume that you have an array with three strings that you want to sort in ascending order according to the length of each string.

  var array = ["The", "quick", "duck"];

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

The function is returning an integer from b.length being subtracted from a.length. Looking at the first two strings, you would be comparing these values:

  return a.length - b.length

This translates to:

  return 3 - 5

3 - 5 returns a negative number (-2). This means that a.length must be a lower value than b.length. Therefore, they are already in ascending order, with (a) having a length of three characters and (b) having a length of five characters. The sequence then moves to the next two strings in the array.

Now, let's compare the second and third strings in the array, which are "quick" and "duck":

  return a.length - b.length

The second string is "quick" and the third string is "duck". This now translates to:

  return 5 - 4

5 - 4 returns a positive number (1). This means that a.length must be a higher value than b.length. Therefore, they need to be swapped in place, resulting in "duck" coming before "quick".

This is able to be done because it is comparing two integers and using the returned value from the minus (-) operator to know which value comes first.

Simply stated, the sort function does not accept boolean (true or false) values, which the greater-than (>) and less-than (<) operators return.

Needed to use a minus instead of a 'less than' symbol. Uhhhh.

This was helpful

did the same thing. totally get it now...

This is the answer my friend:

saying2.sort(function (a, b) {

 return a.length - b.length;

});

Can anyone explain why that is the correct answer? I'm having a hard time understanding the logic behind it. I too used a.length < b.length thinking this would order them from shortest to longest. If someone could explain what exactly is going on in the function to return the value we're looking for that would be very helpful. Thanks in advance!