While working with any language we make use of variables. Variables are used to store values and reuse them in our code. We use different types of variables in our code such as strings (text), integers (numbers), floats (decimal numbers), boolean (true or false) and objects. In PHP we can make use of variable while writing scripts. In this lesson we're going to cover PHP variables.

In programming, a string is a sequence of letters, symbols, characters and arithmetic values or combination of all tied together in single or double quotes. For example, "I Love PHP", "10", '100.01', "", etc are all examples of strings.

Most interactive websites nowadays would require a user to log in into the website’s system in order to provide a customized experience for the user. Once the user has logged in, the website will be able to provide a presentation that is tailored to the user’s preferences.

This article describes the fundamentals of objects and classes in PHP V5, from the very basics through to inheritance, for experienced object-oriented programmers and those who have not yet been introduced to objects.

Marty Lurie describes how to use SQL to analyze the logs of a Web server to understand how people use the site and performance issues. Using Linux clusters with a shared nothing database can improve the performance of that processing. Examples are shown using IBM-Informix XPS Developers Kit.

As a language for building dynamic Web pages, PHP offers a simplified method for constructing complex and powerful Web-related programs. Step by step, Erik demonstrates the fundamental principles of PHP in an original real-world Web site example. In Part 2 of this series, he shows you how the delivery module presents a menu of stories to the reader, and how the authoring module permits authors to submit stories to a Webzine.

As a language for building dynamic Web pages, PHP offers a implified method for constructing complex and powerful Web-related programs.Step by step, Erik demonstrates the fundamental principles of PHP in an original, real-world Web site example. Part 1 of this two-part series offers the basics of PHP and features a Webzine that includes an author's page where content providers can enter the text of articles, as well as a front end for presenting this content to the world.

Part one of this series ended by noting three elements that were lacking in the Simple Linear Regression class. In this article, the author, Paul Meagher, addresses these shortcomings with PHP-based probability functions; demonstrates how to integrate output methods into the SimpleLinearRegression class; and creates graphical output. He then tackles these issues by building a data-exploration tool, designed to plumb the depths of information contained in small- to medium-sized datasets. (In part one, the author demonstrated how to develop and implement the heart of a simple linear regression algorithm package using PHP as the implementation language.)

While the first article in this series discussed building intelligent Web applications through conditional probability, this Bayesian inference article examines how you can use Bayes methods to solve parameter estimation problems. Relevant concepts are explained in the context of Web survey analysis using PHP and JPGraph.

A missing, but powerful, tool in the PHP arena is a language-based math library. In this two-part series, Paul Meagher hopes to inspire PHP developers to develop and implement a PHP-based math library by providing you with an example of how a library of analytic models might be developed. In this first part, he demonstrates how to develop and implement the heart of a Simple Linear Regression algorithm package using PHP as the implementation language. In Part 2, the author adds features to the package for a useful data-analysis tool for small- to medium-sized datasets.

Conditional probability -- the probability of observing one event as a result of having observed another event -- is a potentially important factor in designing intelligent Web applications. Paul Meagher introduces Bayesian inference by discussing the basic mathematical concepts involved and demonstrating how to implement the underlying conditional probability calculations using PHP. In this article, the author discusses how Bayesian inference can be used to build an online PHP-based wizard that guides a user through the process making a medical diagnosis. This three-part series features interesting applications designed to help you appreciate the power and potential of Bayesian inference concepts.

To help developers learn to fit the benefits of probability modeling into Web application development, Paul Meagher introduces you to basic concepts, techniques, and PHP-based tools that define the area of probability modeling and probability distributions. He demonstrates how to develop univariate probability models in PHP; discusses how to fit empirical data distributions to a theoretical probability distribution; and showcases an important tool for all this -- the Probability Distributions Library (PDL).

Effective, multi-level analysis of Web data is a critical element for the survival of many Web-oriented businesses, and the design (and determination) of data-analysis tests is often the job of systems administrators and in-house application designers who may not have an understanding of statistics beyond tabulating raw counts. In this article, Paul Meagher delivers the skills and concepts Web developers need to be able to apply inferential statistics to their Web data streams.

Steve shows how to create personalized Web sites that let visitors customize their view of the site and the information they see. This server-side application, for PHP developers with some experience, stores user profiles in a MySQL database and dynamically generates information using PHP. Steve also introduces the new session management features in PHP4 and discusses efficient PHP coding.

Unless you are stubborn or completely out of touch with reality you should be aware that Google provides the best search results for websites. Search functionality plays an integral role in the user experience for many sites. We will be looking at 3 different options.

In Part 3 of this series on developing efficient PHP code in real-world situations, Amol Hatwar discusses how to build the most efficiently functional functions, functions you can use without sacrificing too much performance or manageability. The author focuses on writing reusable functions and covers how to avoid the most common problems associated with this task.

The series Develop rock-solid code in PHP is about solving practical, real-life problems in medium- to large-scale applications. In this article, PHP veteran Amol Hatwar discusses how to use variables effectively. He also shows how to make script configuration easy by constructing a configuration file parser using variable variable names in PHP.

The Develop rock-solid code in PHP series is about solving practical real-life problems in medium- to large-scale applications. With a sharp focus on new features available in PHP 4, the articles shed light on numerous tips and tricks that make life easier. Inside, you will find plenty of examples and techniques to learn, with lots of sample code. In this first article, PHP veteran Amol Hatwar gives a higher perspective for designing and writing bug-free, maintainable code for medium- to large-scale Web applications.

Joe Brockmeier presents a brief introduction to the PHP scripting language with a discussion of PHP's origins, capabilities, and the platforms it's available on. A simple PHP script example highlights basic syntax and usage.

Effective, multi-level analysis of Web data is a critical element for the survival of many Web-oriented businesses, and the design (and determination) of data-analysis tests is often the job of systems administrators and in-house application designers who may not have an understanding of statistics beyond tabulating raw counts. In this article, Paul Meagher delivers the skills and concepts Web developers need to be able to apply inferential statistics to their Web data streams.

One of the advantages of PHP has always been the ability to easily manipulate information submitted by the user through an HTML form. In fact, PHP version 4.1 adds several new ways to access this information and effectively removes the one most commonly used in previous versions. This article looks at different ways to use the information submitted on an HTML form, in both older and more recent versions of PHP. It starts out by looking at individual values and builds to a page that can generically access any available form values.

Every good website should not only be functional, but also look good. Why would that exclude the address bar of the user's browser? It doesn't. Even with dynamic content you can have clean and even uber cool urls for all of your pages. No one wants to see your question marks and ampersands. Even numbers are boring.

Find out how to script in PHP, an open-source embedded scripting language for HTML. You'll learn how to install and configure PHP for use with the Apache Web server on UNIX or the Microsoft Internet Information Server on Windows NT. Then you'll see by example how to use PHP to route HTML conditionally, to develop a simple database-driven Web application, and to track user sessions with cookies.