First, you’ll need a MySQL result set. To do that you’ll need to select something from your database and loop through it like so:

$result = mysql_query("SELECT * FROM my_table");

while($row = mysql_fetch_assoc($result)) {

// inside the loop

}

The problem is, if you want to loop through the same result set again, you will get an error because the internal pointer is currently at the end of the result. You will need to put the pointer back at the beginning of the result set so that you can loop through it again.

You can do it with a helpful php function named mysql_data_seek.

mysql_data_seek($result, 0); // set the pointer of the result set back to the beginning.

while($row2 = mysql_fetch_assoc($result)) {

// inside the loop

}

This demonstrates how, as a PHP website developer, you can reset the pointer of a MySQL result set, which will allow you to iterate through the result set for a second time.

The ternary operator is a shorthand if/else statement. It allows developers to form conditions quickly and in a very readable fashion.

Here is the ternary syntax

(condition) ? true-stuff-here : false-stuff-here;

Here is an example of the ternary operator

$age = 20;

$response = ($age > 29) ? 'He's in his thirties' : 'He's not';

echo $response; // He's not

I hope you can see the usefulness in the ability for the ternary operator to easily perform conditional comparisons. Please however, refrain from using ‘nested ternary comparisons’ as the are very difficult to so read. It is so frowned upon by web developers that I’m not even going to post an example.

Sorting a PHP Array by Date

The first step is ensuring that the dates are placed into the array in proper format. When you add the date to the array, the best and most compatible way to do do is to run the PHP date function on the date value. This function works no matter what format the date is in, including a MySQL datetime column or a PHP timestamp.

So to enter dates into your array you can do something like:

$dateArray[] = date('Y-m-d');

//If you are iterating through something like a database with date's you could do something like:

$dateArray[] = date('Y-m-d', $row['date']);

One you have your date array set

All you need to do is run a  sorting function on the array.

Most recent date first

rsort($dateArray);

Oldest date first

sort($dateArray);

I hope this quick tutorial will help you in your website development and design endeavors!

About This Craigslist Clone

This script is a framework that can be used to get your classifieds site up and running quickly.

Classifieds Features

• Users can register / login / logout
• Users can post a classifieds ad
• Users can post images
• Admin’s can set categories in database
• Admin’s can set locations in database
• Admin’s can easily skin the script to fit within their already running sites / templates
• This script is completely free for website developers to use in any of your personal or commercial scripts and websites.
• The entire script is organized into an easy to understand filesystem with easily to use classes and methods.

What you can use this classifieds script for

To best use this script, you are going to need to integrate it into your own website design. You should have some knowledge of HTML/CSS to do this. You don’t need any knowledge of PHP, just copy the the text between the php tags inside of your HTML.

Usage

• Install the classifieds.sql file into your database (via phpMyAdmin or something similar)
• Open Db.php and input your database credentials
• Open URLs.php and in put the location where you installed the classifieds script
• Start skinning and using the script!

Feel free to contact me if you would like me to extend the features or customize this script for you on a contract basis. I’m a local Miami Website Designer and Developer that has worked on  an array of different types of web development projects.

The function to check if value is within a two number range

function numberBetween($numToCheck, $high, $low) {
if($numToCheck <= $low) return false;
if($numToCheck >= $high) return false;
return true;
}

How to call the function

if (numberBetween(35, 100, 20)) {

echo 'The value is in the range!';

} else {

echo 'The value is outside the range!';

}

In this example, the value returned would be true because 35 is between 100 and 20.

I hope this data validation function will help you in your website development endeavors. It should simplify your development of a function that checks to see if a number (integer) falls between two values (range of numbers).

The URL Data Validation Function

function validateURL($URL) {
return (bool)preg_match("/^(http|https|ftp):\/\/([A-Z0-9][A-Z0-9_-]*(?:\.[A-Z0-9][A-Z0-9_-]*)+):?(\d+)?\/?/i", $URL);
}

How To Call The Function

if (validateURL('http://www.krio.me') {

// If URL is valid, do something here

}

Use this in all of your PHP scripts to ensure that input provided by users for URL’s is of a valid data type. Need a website developer to help you out? Contact me if you need some help. I’m a web developer and designer local to Miami, Florida.

Our XML File

Here is our XML file.

We are going to insert a new <Link> child element that holds sibling elements <title> and <url>.

<?xml version="1.0" encoding="ISO-8859-1"?>
<MyLinksCentral>
    <Links>
        <Link>
            <title>Krio Media</title>
            <url>http://www.krio.me</url>
        </Link>
        <Link>
            <title>SEO Miami</title>
            <url>http://www.mercadeoporinternet.com/</url>
        </Link>
    </Links>
</MyLinksCentral>

How To Add The XML Elements

And here is how we add the new elemnts to the document

  $xdoc = new DomDocument;
  $xdoc->Load('MyLinksCentral.xml');

        $links = $xdoc->getElementsByTagName('Links')->item(0);
        $newLinkElement = $xdoc ->createElement('Link');
        $newTitleElement = $xdoc ->createElement('title');
        $newURLElement = $xdoc ->createElement('url');

        $urlNode = $xdoc ->createTextNode ('Google');
        $titleNode = $xdoc ->createTextNode ('http://www.google.com');

        $newTitleElement -> appendChild($titleNode);
        $newURLElement -> appendChild($urlNode);

        $newLinkElement -> appendChild($newTitleElement);
        $newLinkElement -> appendChild($newURLElement);

        $links -> appendChild($newLinkElement);

$xdoc->save('MyLinksCentral.xml');

Step-By-Step Analysis Of The XML

Load – We load the XML file.

getElementsByTagName – We get the Links element, which holds all of our links.

createElement – We create the elements that we will be inserting into our XML file and save them into a variable.

createTextNode – We place the values of the elements into variables. In this case it is the URL and Title we want. We we will inserting Google as the Title and http://google.com as the URL.

appendChild – We put the text we just created into the actual elements <title> and <url>.

appendChild – The next set of appendChild’s are to place the complete <title> and <url> tags inside of our <Link> element.

The final appendChild is to insert the final <Link> tag into the <Links> element of the XML file to be saved.

I had to develop a web scraper for a proof-of-concept application a few months ago in PHP and since have had a few questions on how to implement them. I decided to make a post and include the web scraper free of charge for other developers to download and utilize in their scripts.

What This Scraper Does

This scraper uses the cURL PHP library in combination with 10 of the most popular search engines to gather information. First, it takes a string as a query provided by the user and searches the internet for sites relevant to that search query. It then visits and scrapes these sites for whatever regular expression you provide to it and stores these results into an array that can be placed into a database, xml file, or anything similar.

I wanted to write this article to give both my opinions and observations since I started using PHP in the mainstream business world. Lots of people have a poor view of PHP and its usage for business applications and complicated development sites. I’m going to explain why individuals and other website developers have this misconception and ways that PHP developers can improve their coding so that these myths can be forgotten.

One of the main reasons PHP is seen in a poor light is due to programmer inexperience. PHP is the next logical step for a web designer after they learn CSS and HTML because the barrier to entry is so low. Servers and inexpensive and the majority of designers and developers can easy use PHP scripts on their servers without any type of installation or configuration. This means that a higher percentage of new programmers and developers are using PHP, thus they may be using poor coding standards and bad practices.

Why So Loose?

PHP is a loosely typed language, which means that developers must be very careful when evaluating and comparing variables, because of this reason, new programmers (and even experienced developers from other languages) will have a difficult time writing effective code that evaluates properly.

$myNum1 = 1;

$myNum2 = '1';

if ($myNum1 == $myNum2) echo 'Hey, they're equal! Well not really because one is an integer and another a string, BUT WHO CARES!';

if ($myNum1 === $myNum2) echo 'Hey, they're NOT equal! And this time, I'm right!';

Developer Coding Standards

Best practices are often something that inexperienced developers don’t follow, mostly because they don’t know that they exist. The majority of PHP programmers will follow the Zend guidelines for best programming practices. If a company you go to work for does not follow the Zend coding standard guidelines, they surely will know about them, and you will easily be able to transfers this knowledge to whatever they are using. Its not so much about choosing which standards are right, but more about weeding out the poor standards that virtually everyone agrees on.

My List Of The Most Common Errors / Inefficiencies

• Placing database calls and code within presentation and logic code
• Note reusing code (See my introductory tutorial on developing in OOP with PHP)
• Not filtering user input
• Copying internet tutorial code and not reviewing it
• Not planning to scale or understanding how to
• Using a framework without first understanding the raw language

What These Errors Cause

• Exploits, such as SQL injection and cross-site scripting
• Cluttered code that slows down future development
• Debugging difficulties

How To Improve The Misconceptions

• Learn about caching both database calls and your code
• Figure out how to sanitize input
• Learn programming fundamentals and standards
• Make sure PHP is the right tool for the job

New developers are often the reasons for PHP having such a bad reputation with big business. Experienced programmers can write excellent PHP code that is more efficient and effective than other popular web programming languages, however the ability for anyone to start writing PHP code has been both a blessing and a curse upon the language.

Developers will often read a framework’s site and see promises like ‘Improve your development time by 50%!’. Well, all seems great, except that inexperienced programmers will take this to heart before they even start writing real PHP code, which often-times leads to a bloated code-base.

PHP Is Slow

This is true. PHP is a language that will always need to utilize caching on all projects with high traffic, however this problem is not PHP specific. If your’re developing a high traffic PHP application, you need to research memcached.

Other Things To Remember When Developing PHP Code

PHP was created as a web templating engine, it was not meant to be an all-encompassing language. You should understand this before beginning to develop with it. What framework should I use? I hear Smarty is great! What about Codeigniter? First off, if you really need to ask which is the BEST, you probably have no clue how to actually use these tools to your advantage and should really stick with PHP until you have a firm understanding of it. Second, most developers critize templating engines like Smarty, because PHP was initially created as a web templating engine, so you going to template the template? Well, thats another topic all-together.

If you’re getting into PHP, I hope that this article has helped you to gain some understanding of areas that you should place some time when learning to develop PHP scripts and applications.

Why is learning object oriented programming so hard?

Learning object oriented programming is the next logical step for any web developer wanting to advance their career. Many website developers put off this step either because they don’t see its relevance or because they find it confusing. The main reason I noticed when I first started out was lack of use. Because there are alternative ways of writing code, individuals would rather not use OOP and use the procedural alternative, and as most of us know, the only way to advance knowledge of programming is through actually programming. It wasn’t until I started to learn C# that I actually started to apply OOP to my PHP work, mostly because in C# you have to use OOP so I picked it up very quickly.

I’m going to go over the basics of object oriented programming with PHP and hopefully clear up some of the confusion by using examples that relate directly to what you are probably doing on a daily basis as a PHP programmer. Once you start picking up these skills, make sure to USE THEM on a daily basis and everyday implement something new related to OOP or you will definitely never really learn to be effective with it. If you are reading this, I’m going to assume you probably now what OOP is and have tried to learn it before.  I’m not going to go over what OOP is, just HOW to use it with real world examples in PHP.

A Useful CSS Class

This class will allow you to develop an application to create CSS dynamically depending on whatever input you give it.

class DynamicCSS
{
    protected $lineOfCSS = array();

    public function addCSS($property, $value)
    {
        $this->lineOfCSS[] = array("property" => $property, "value" => $value);
    }

    public function run()
    {
        foreach ($this->lineOfCSS as $array) {
            $this->outputCSS($array['property'], $array['value']);
        }
    }

    public function outputCSS($property, $value)
    {
        echo "{$property}: {$value};";
    }
}

$css = new DynamicCSS();
$css->addCss("display", "none");
$css->run();

This class has an array named lineOfCSS, that will hold each line of CSS that we give it. It has the addCSS method that will handle adding the line to the array. It also has the run method, which will iterate through the array and pass the line to the outputCSS method, which will output it to the screen.
The $this keyword is used to signify the use of a variable related directly to the specific instance of an object from the class you are currently using. If you have multiple objects from the same class, they all have their own variables and do not influence one another.

Interfaces

Think of an interface as a blueprint of methods that your classes can use. It is a skeleton that you can build off of later. Think of an interface as a way to link classes that are similar. Interfaces ensure that a class always has a specific method and that you never get a method undefined error.

To use an interface, your class must implement it.

interface dbConnections {

function update();

function select();

}

class Db implements dbConnections {

public function update()  {

// update code here

}

protected function select()  {

// select code here

}

}

The interface makes sure that the Db class has an update a select method.

This example brings us to our final example every developer should know.

The private, protected, and public keywords.

Private Keyword

If a variable or method is labeled private, it can only be called from the class that it is declared in.

Protected Keyword

Protected variables and methods can be called from the class they were declared in and any class that is extended from this class.

Public Keyword

Variables and methods labeled public can be called from anywhere in the script.

Final Keyword

The final keyword is used on methods to ensure that is cannot be changed or overwritten. The following code will throw and error.

class Display
{
final public function image()
{
echo "<img src='img.jpg'/>";
}
}
class DisplayAgain extends Display
{
public function img()
{
echo "<img src='img2.jpg'/>";
}
}>

I hope this introduction to object oriented programming has cleared up any confusion that you may have had. I’m going to turn this into a series now that the foundation has been set that will integrate more OOP and PHP topics to improve your website development skills.