PHP

Explore PHP, one of the most popular Web programming languages in use today. Learn how PHP works and how to write useful PHP scripts and applications.

Build a CMS in an Afternoon with PHP and MySQL

21 January 2011 / 608 Comments

View Demo » | Download Code

14 May 2019: This article and the code were updated for PHP7 compatibility.

Building a content management system can seem like a daunting task to the novice PHP developer. However, it needn’t be that difficult. In this tutorial I’ll show you how to build a basic, but fully functional, CMS from scratch in just a few hours. Yes, it can be done!

Along the way, you’ll learn how to create MySQL databases and tables; how to work with PHP objects, constants, includes, sessions, and other features; how to separate business logic from presentation; how to make your PHP code more secure, and much more!

PHP References: How They Work, and When to Use Them

19 November 2010 / 17 Comments

References are a very useful part of PHP and, for that matter, most other programming languages. However, references can be somewhat confusing when you first start learning about them.

This tutorial is a gentle introduction to references in PHP. You find out what references are, and how they work. You learn how to create and delete references, as well as pass references to and from functions. You also explore some other uses of references, and discover situations where PHP creates references automatically on your behalf.

PHP Variable Scope: All You Need to Know

15 October 2010 / 6 Comments

When you’re just starting to work with functions and objects in PHP, variable scope can be the cause of some confusion. Fortunately, PHP’s scope rules are relatively easy to understand (compared to some other languages, at least!).

In this tutorial you’ll learn all you need to know about variable scope in PHP. You’ll look at:

The concept of variable scope — what it is, and what it means
The differences between global and local scope
How to access global variables from within a function
PHP’s superglobals, and how they work
How to use static variables to preserve state

Let’s get started!

Make Your Own PHP Functions: The Newbie Guide

16 September 2010 / 4 Comments

You’re no doubt familiar with using functions in PHP. The language contains hundreds of built-in functions that you can use for all sorts of handy jobs — from manipulating text through to reading files, sending email messages and processing images.

You’re not limited to using just the predefined functions, though — you can create your own functions too! In this tutorial, I’ll show you how. You’ll learn:

Why it’s good to create your own functions
How to create and use a function
How to make your functions flexible by using parameters
All about optional parameters and default values, and
How to return values from your functions.

Ready? Let’s get started!

Easy Ways to Sort Arrays in PHP

16 August 2010 / 2 Comments

As I mentioned in my earlier article, Creating Arrays in PHP, arrays are very useful if you need to store and manipulate a large amount of data in one go. One useful way you can manipulate this data is to sort it in a particular order.

PHP gives you a large number of sorting functions that can sort arrays using many different criteria. For example, you can sort in ascending or descending order, by key, or by value. These functions make it really easy to sort arrays without getting bogged down in the details of sort algorithms.

We won’t try to cover every single PHP array-sorting function in this tutorial. Instead, you’ll learn about the functions that you’re likely to find the most useful in your everyday coding.

Let’s get started!

Using Multidimensional Arrays in PHP

19 July 2010 / 13 Comments

Array elements in PHP can hold values of any type, such as numbers, strings and objects. They can also hold other arrays, which means you can create multidimensional, or nested, arrays.

In this tutorial you learn how to create multidimensional arrays, how to access elements in a multidimensional array, and how to loop through multidimensional arrays.

Using foreach to Loop Through PHP Arrays

27 May 2010 / 2 Comments

Often you need to move through all the elements in a PHP array so that you can do something with each element’s value. For example, you may want to display each value in an HTML table, or give each element a new value.

In Counting PHP Array Elements Using count(), I showed how you can use a for loop along with the count() function to loop through an array. However, there’s a much easier way to loop through arrays: the foreach construct.

In this article you learn the basic syntax of foreach, and see how to use it to loop through both indexed and associative arrays.

Counting PHP Array Elements Using count()

6 May 2010 / Leave a Comment

Often it’s useful to know how many elements an array contains. Here are some common reasons for counting the number of elements in an array:

You can then use a for loop to move through the elements
You can display the total number of elements to the user (such as the number of search results returned)
You can calculate the average of the values in the array (in conjunction with array_sum())

PHP makes it easy to count array elements, thanks to its built-in count() function. In this tutorial you’ll learn how to use count() to count the elements in both regular and multidimensional arrays, and how to move through all the elements of an indexed array by using count() and a for loop.

Extracting Elements from PHP Arrays with array_slice()

30 March 2010 / Leave a Comment

In Working With Array Elements in PHP, you saw how to read and change individual elements within a PHP array. However, sometimes it’s useful to work with a range of array elements. For example, you may want to work with a large array in chunks, or sort an array then retrieve just the “top 10” values from the start of the array.

In this tutorial you’ll explore PHP’s array_slice() function for extracting a range of elements from an array.

Working With Array Elements in PHP

19 March 2010 / Leave a Comment

In Creating Arrays in PHP, you learned how PHP arrays work, and saw how to create an array using PHP.

In this article you take things further, and look at how to access the individual elements inside a PHP array. You’ll see how to:

Read element values
Alter element values
Add and remove elements in an array
Output the entire contents of an array

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