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sort

They wait their turns, eventually moving to the front of the line where they buy their tickets. After the

purchase is complete, the people leave the front of the line and go into the movies (Figure 3-4). This is

traditionally called

get

dequeue

Figure 3-4

Although the names of the methods aren’t the same, the functionality is the same. You add items to the

queue using the

push()

method (adding items to the back of the array) and remove items from the

queue by using the

shift()

method:

var queue = [“red”, “green”, “yellow”];

queue.push(“black”);

alert(queue.toString()); //outputs “red,green,yellow,black”

var sNextColor = queue.shift();

alert(sNextColor); //outputs “red”

alert(queue.toString()); //outputs “green,yellow,black”

In this example, the string

“black”

is added to the back of the queue by using the

push()

method. In

order to get the next color, the

shift()

method is used to retrieve

“red”

, leaving the queue with only

“green”

“yellow”

, and

“black”

Two methods relate to the ordering of items in arrays, the

reverse()

and

sort()

methods. The

reverse()

method, as one might expect, simply reverses the order of the items in an array. So if you

want to reverse the order of

“red”

“green”

“blue”

, you do this:

var aColors = [“red”, “green”, “blue”];

aColors.reverse();

alert(aColors.toString()); //outputs “blue,green,red”

The

sort()

method, on the other hand, arranges the item in the array by sorting them into ascending

order based on their values. To do this sort, transform all values into strings by calling their

toString()

method. The items are compared by character code (as I described in the section on using the less-than

operator on strings). For example:

var aColors = [“red”, “green”, “blue”, “yellow”];

aColors.sort();

alert(aColors.toString()); //outputs “blue,green,red,yellow”

234

2 34

1234

Star t

Get

Result

Chapter 3

06_579088 ch03.qxd 3/28/05 11:36 AM Page 76