Implicit Evaluation with PHP Archives: Arrays
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22 February 2007
Generating SQL Insert Queries
Its possible to generate a well formed SQL query with one line of PHP by capitalizing on lambda-style functional support.
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23 January 2007
What is $_REQUEST, or the difference between $_REQUEST, $_GET and $_POST
PHP provides you a number of “super-global” variables. These include $_GET, $_POST, $_COOKIE, $_SESSION, $_SERVER, $_ENV, $_FILES and $_REQUEST. Most of these are fairly self-explainatory. $_GET are the variables passed by forms with a GET method or after the end of the path such as example.com/search.php?GETARG1=GETVAL1&foo=bar. $_POST is any variable submitted by a form with […]
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18 January 2007
Loops in PHP
PHP gives programmers many varieties of loops to work with. Despite an overwhelming selection, each is tailored, really, to just one scenario.
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1 January 2007
Recursive Data Structures in PHP
Welcome to the Jungle
Today, I was helping a friend implement a recursive category model. There is a top level category and each category contains items and sub-categories.
It’s easy to illustrate on the web:
Top Level Category
Item 1.1
Item 1.2
Subcategory 1.3
Item 3.1
Item 3.2
Subcategory 1.4
Subcategory 4.1
Subcategory 4.1.1
Item 4.1.1.1
Item 4.1.1.2
Item 4.1.2
Somehow, your web browser can take a piece of text […]
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7 December 2006
The Difference Between PHP’s Globals and Superglobals
PHP only has two variable scopes: local and global. But it has three considerations for scoping variables: local, global and superglobal. What exactly is a superglobal?
The only superglobal variables in PHP are
$_POST
$_GET
$_REQUEST
$_COOKIE
$_SERVER
$_SESSION
$_ENV
$_FILES
These are the variables that PHP just gives you which few other languages offer. There is no way to create your own superglobal but […]
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20 November 2006
Comparing array_key_exists With isset
There are two functions for determining the existence of elements in an array: isset and array_key_exists. They are very similar in use, but there are subtle differences.
The biggest difference is speed. array_key_exists takes about 33% longer to execute than isset. For just a few checks, it’s a negligible difference. But in a loop, it will […]
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24 October 2006
Session Management in PHP
Session management is one of the features that sets PHP apart from other languages which happen to be used on the web. It is easy enough to understand how to use $_SESSION, but many programmers seem to learn how to use it and nothing more.
$_SESSION serves a single, useful purpose. It makes variables available across […]
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27 September 2006
Tail Recursion in PHP
There are two types of recursion in the world: tail recursive and non-tail recursive. Non-tail recursive is the more obvious of the two and is used frequently. For instance, when dealing with any kind of hierarchical data (that which is expressed in a tree data structure) a recursive call is likely used to construct the […]
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26 September 2006
Variable Numbers of Arguments in PHP
There is a problem which infrequently appears in nearly every programming language: calling a function with a variable number of arguments. It is interesting from both sides of development: if you’re writing a function, how will you collect variable numbers of arguments? If you’re consuming a function, how will you provide the arguments?
Much of the […]
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1 May 2006
Accessing Multi-dimensional Array
This weekend, I got an email from a reader wondering how to access non-constant indices of a multidimensional array.
Given an HTML field like <input name=”users[username][email]” type=”text” />
He needed to know how to access it. After trying multiple things, the solution he found was:
$property = “[username][email]”;
$field = $_POST[”users”];
$result = eval (”$field$property;”);
The more obvious $result = […]