In this article I will explain arrays and how they are used in PHP. The PHP Manual defines an array in PHP as an ordered map. Personally, I don't like this definition. I will define an array in PHP as a collection of variables, which I think is a little more descriptive. In most languages, at least the ones I am familiar with, the variables in this collection must all be of the same type. Not so in PHP! This is because of PHP's Type Juggling. I'm not going to go into great detail about Type Juggling, but basically it means that you don't declare a variable as a certain type. The context in which the variable is used determines its type. So, how do you assign values to arrays? The exact same way as you would any other variable, except that you specify which element of the array you wish to work with. One important thing to note is that, by default, arrays start numbering their elements at zero. Check this out: <?php
$array[0] = 3;
$array[1] = 6;
$array[2] = 2;
?> |
A cool feature of PHP is the ability to use associative arrays. Associative arrays give you the ability to name your array's keys. So, instead of having $array[0] and $array[1] you can have $array['something'] and $array['anotherthing']. So what's the big deal? Why would I want to use arrays rather than just regular old variables? Imagine this: You are working with customer's names. You have 5 of them that you continually need to echo out. With regular variables, you would do it like this: <?php
echo "$customer1<BR>\n";
echo "$customer2<BR>\n";
echo "$customer3<BR>\n";
echo "$customer4<BR>\n";
echo "$customer5<BR>\n";
?> |
Pretty long winded. Imagine doing that with 100 customers. Or 1000. With arrays, you can use a foreach loop. What a foreach loop does is loop as many times as you have elements in an array. Suppose you had an array called $customer that contained your customer names. Check this out: <?php
foreach($customer as $value) {
echo "$value<BR>\n";
}
?> |
Now how easy is that? That code will not change if you have 100 or 1000 customers. That's the beauty of arrays. Ok, that clues you in on some simple arrays. What about multi-dimensional arrays? What are they? Let's take a look at a two-dimensional array as an example. Say you are dealing with selling books. You want to place the names and prices of these books into an array. What you would want to do is create an array where each element is an array. Sound confusing? It really isn't. Take a look at this example: <?php
$books = array(0=>array('name'='A Book','price'=>9.99),1=>array('name'='Another Book','price'=>17.99));
?> |
Now, here are a couple ways to access that data in our two-dimensional array: <?php
echo $books[0]['name'];
echo $books[1]['price'];
$books[0]['price'] = 12.99;
foreach($books as $onebook) {
echo $onebook['name'] . " sells for $". $onebook['price'] . "<BR>\n";
}
?> |
There you have it. A simple introduction to arrays in PHP. I hope it was helpful to you. For more info, check out the PHP Manual. There are a whole bunch of functions in there that can be used with arrays. | DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware. |
More Programming Basics Articles
More By Matt Wade  developerWorks - FREE Tools!
|
Hold your calendar on January 30, 2008 for this free webcast on the new i5/OS. Rational's Enterprise Modernization products will be discussed at this webcast as they help to drive the application development environment for this new System i OS. <br />And learn how i5/OS will take you to the next step of efficient, resilient business processing. You will hear about the new i5/OS capabilities as it will be the most significant i5/OS release in years. If you cannot join the webcast on 1/30/08 you can still use this link to listen to the replay.<br />
FREE! Go There Now!
| | | |
This demonstration gives you an overview of IBM® Rational® Build Forge Express Edition, a global offering that provides a framework to automate and execute software processes. Rational Build Forge provides a software assembly line that can support all of your tools, technologies, and platforms so you can achieve a repeatable, reliable, and traceable build and release process.
FREE! Go There Now!
| | | |
Join this webcast, to learn how the Rational Process Library can help with compliance issues, drive process improvement, and assist in service-oriented architecture (SOA) or Agile development. We will take a peek into the Rational Process Library with content around software and systems engineering (including RUP), operations and systems management, program and portfolio management, and asset and SOA governance.
FREE! Go There Now!
| | | |
Visit IBM developerWorks to download a free trial of the latest release of IBM Lotus Sametime Standard V8.0. Lotus Sametime Standard V8.0 is a platform for unified communications and collaboration that combines security features with an extensible, open solution including integrated Voice over IP, geographic location awareness, mobile clients, and a robust Business Partner community offering telephony and video integration.
FREE! Go There Now!
| | | |
As systems increase in complexity, communication between systems and software teams becomes more and more difficult. Now, there’s a way to improve product quality and communication.<br />Read the “Model Driven Systems Development” white paper to see how. Also included in this kit are more educational white papers, customer examples, tutorials, informative Webcasts, and best practices for designing, building and managing systems.<br />
FREE! Go There Now!
| | | |
Learn how Rational Build Forge can extend a simple compile and package build process by adding customization and deployment capability. Go from a manual method to automating: checking for code changes; getting the latest source; compiling and packaging; customizing; copying to and restarting a deployment server; and sending e-mail notification that a new version is available.
FREE! Go There Now!
| | | |
Asset Reuse is a key strategy for companies looking to create innovative solutions to solve complex software development problems. Searching for, identifying, updating, using and deploying software assets can be a difficult challenge. Listen to this webcast, to learn about strategies and tools that you can leverage for a successful project, including Rational Asset Manager, Rational Software Architect and WebSphere Service Registry and Repository.
FREE! Go There Now!
| | | |
This paper is about the critical role that a discipline called integrated requirements management can play in helping to ensure that your business goals and IT investments are continuously aligned—whether you are sourcing, integrating, building or maintaining software. It also looks at ways that automated IBM Rational® products can work together to help you use requirements in the very best way.
FREE! Go There Now!
| | | |
Explore how Rational and WebSphere software enable enterprise documentation in SOA environments. Specifically, a new integration between IBM WebSphere® Business Modeler and IBM Rational® Method Composer software can help technical writers more easily keep enterprise operations manuals in sync with changes that are made to business processes, resulting in more accurate and timely documentation that benefits the entire enterprise.
FREE! Go There Now!
| | | |
With IBM Rational Systems Development Solution, you can deliver products faster with higher quality. Within this kit, Read the “Model Driven Systems Development” white paper to see how to improve product quality and communication. Then check out the rest of the e-Kit to learn more about important topics that can affect the success of any software project through customer examples, tutorials, informative Webcasts, and best practices for designing, building and managing systems. From start to finish, at every stage in your projects, Rational Systems Development Solution can help your company reach its full potential.
FREE! Go There Now!
| | | |
All FREE IBM® developerWorks Tools!
| |
