Before you check out the code, let’s take a look at the three keywords related to the exceptions.

• Try – Inside the try function block we’re checking if a particular programming logic triggers an exception.
• Throw – If the program finds an exception in try block we throw an exception using throw keyword.
• Catch – This is the block where an object is created with exception information.

Check the below code to see how an exception handling program works.

<? php try {     $checkvar= 'testing error';     throw new Exception($checkvar);
echo 'ine is skipped by compiler as it moves directly in catch block after throwing an exception'; }
catch (Exception $e) {
echo 'Found an exception: ',
$e-&gt;getMessage(), "\n";
}
 
echo 'Exception program demo;
?>

In try block we’re creating a variable and throwing a new exception when compiler finds it. Any line after the throw keyword is not executed as the entire block is skipped to catch. So any code below the throw keyword is skipped. Inside catch block an exception is thrown and you get the error message printed. After this the last echo statement is printed on webpage.

Points to Remember:

• An exception can be caught or thrown with the help of php block.
• There should be atleast one catch block for corresponding try block.
• Exceptions can be thrown or rethrown within a catch block.

You can use the exception handling while working with php file handling or network connection related programs. I hope this helps you to understand the exception handling in php. If you have any questions, suggestions related to this tutorial, feel free to comment. If the comments are expired on this post, feel free to use twitter to ask me.

In file handling you’re basically doing following simple steps.

• Create a file.
• Assign an object to open the file.
• Read or write on the file.
• Close the file.

These four steps remain the same for every file management program in php or any other language. You just have to insert any other optional logic combining with these four steps. So let’s take a look at how to create a file using php program.

The fopen() and fclose() function

Let’s start with creating the file. In this example we’re going to assign file object to a variable. After that we’re going to open the file for writing with fopen() function and in this process if php fails to find the file, It’ll process the error message in the die() function. At the end we’re calling fclose() function to close the file.

<? php
$dm_f="demophp.txt";
$dm_file=fopen($dm_f,'w') or die("can't find file");
fclose($dm_file);
? >

Note that we’re using the access mode “w” here which means we’re opening the file for write operations. You can use “r” mode if you wish to just read the file. In case of write only data is erased from the previous write and the new data is written on the file. You can use “a” append mode for appending the data to the file.

Writing to File

Check out the following code :

< ? php
$dm_f="demophp.txt";
$dm_file=fopen($dm_f,'w') or die("can't find file");
$dm_fw="this is new text\n";
fwrite($dm_file,$dm_fw);
$dm_fw="this is another one\n";
fwrite($dm_file,$dm_fw);
fclose($dm_file);
? >

In Line 1: we’re creating a demophp.txt file and in Line 2: we’re creating file instance to write on our demophp.txt file. In Line 3: we’re creating a string that we’re going to add with the help of fwrite() function into our demophp file. Every time we created string, we used fwrite() function to pass it to the text file and at the end we closed the file using fclose() function.

You can also experiment with the access mode ‘a’. Why? In case of making log files or creating any file that adds the data on regular period will need both previous and current data and in that case append is useful.

Reading a File

< ? php
$dm_f="demophp.txt";
$dm_file=fopen($dm_f,'r') or die("can't find file");
$dm_fr=fread($dm_file,100);
fclose($dm_file);
echo $dm_fr;
? >

Reading a file follows the same format. You’re going to create a file then open that file with read access mode. By using fread() function you’re going to read the instance of file object by explicitly mentioning how many characters you want to read. In our example we’re using 100 as a fixed number. At the end we’re closing the file and then echoing the data read by variable.

Deleting the File unlike function()

<  ?php
$dmf="thisfile.txt";
unlink($dmf);
? >

Just be careful when you use unlink function as it deletes the content of the file from your server or disk. Deleting is very simple, you just have to pass the file object to the unlink() function. Just make sure you create another program to create the file and verify the existence before you use unlink() function. That way results are noticeable to you.

Hope this tutorial helps you to manipulate files using php. Feel free to let me know your feedback in comments.

We’re covering both webservers here so skip the steps of webserve which doesn’t apply to you.

Xampp and Codeigniter Setup:

First thing we are going to do is setup Xampp for those who want to use codeigniter with xampp. So go ahead and download either portable version or developer version of xampp. Install it in the directory (and drive) as per your choice. Once you copy all the files of xampp in directory, find the start.bat file to start the xampp server. You can also click on xampp control panel to manually start xampp services.

Second Download Codeigniter and extract the files in “htdocs” folder of xampp. You can make the path something like this : /htdocs/codeigniter or /htdocs/ci. You can also rename the codeigniter folder as per your choice.

You can start the server and test the codeigniter setup at http://localhost/codeigniter or if you have renamed the codeigniter folder to something else, use that name.

Uniform Server and Codeigniter Setup:

Unifrom server is very easy to setup and is much better to manage sometimes compared to xampp. You can download uniform server and extrac it to the drive (and in turn directory) of your choice. Once extracted, navigate to the following directory: \UniServer\udrive\www. Inside the ‘www’ folder you have to extract the codeigniter. You can rename codeigniter to something simple if you wish that will definitely help while coding multiple codeigniter projects.

Start the server by going to following address: http://localhost/CI.

You will see the image as shown below in the screenshot.

If you want to create your own welcome message for the application, you should edit the following file.

application/views/welcome_message.php

This completes our simple codeigniter setup tutorial. In next few tutorials, we will see how to setup dynamic websites and later in more advanced tutorials we will check out how to create simple blogs and forums. I hope this simple tutorial helps you to setup codeigniter on your development server.

PHP allows you to use two types of regular expressions.

• POSIX Regular Expressions
• PERL Style Regular Expressions

I suggest you to follow the PERL Compatible Regular expressions as they’re widely used. There isn’t much difference between POSIX and PCRE but you’ve to learn separately to know them better.

There are ways to explain the valid and invalid patterns of regular expressions. I suggest you to use the examples to learn about these valid patterns. This is the reason I am not going to explain you every little expression, Instead you’ll learn from the examples posted here.

Let’s take a look at important perl compatible regular expression functions.

preg_match() : This function performs a regular expression match. Check the following code to see it in action.

<? php
$str="this is demo";
$str1=preg_match("/this/",$str);
$str2=preg_match("/that/",$str);
echo $str1;
echo "<br/>";
echo $str2;
? >

Check the output and you’ll see that it shows 1 and 0. Here value 1 means we have found match and 0 means that there is no match. You can process much more complex data with the help of loops and reg operators.

preg_replace(): This function performs regular expression search and replace operation. See the following code so that you get idea of how preg_replace() works.

<? php
$data="Here is some simple text";
$find="/is/";
$replace="is our";
echo preg_replace($find,$replace,$data);
? >

There are two more optional arguments that you can pass to the preg_replace() to count the replacements and also to restrict the number of replacements of text.

preg_split(): This function takes your input and then split the input into multiple arrays. The value in array is dependent on your operator usage for spliting the text. PREG_SPLIT_NO_EMPTY argument ensures that no empty results are passed to the output of array. Check the following code on preg_split and see how we’re spliting the two statements that are separated with dot.

<? php
$data="Here is some simple text. Run the program";
$prodata=preg_split('/\./',$data,-1,PREG_SPLIT_NO_EMPTY);
print_r($prodata);
? >

Check the output and you’ll see that it splits the sentences in two arrays starting from [0].

This was just short introduction on regular expressions in php. You can read more about regular expressions in general from wikipedia. If you’re python programmer then do read python regular expressions tutorial.

Feel free to let me know your suggestions and feedback on this tutorial. I would love to improve if there are any constructive criticisms in the comments.

You can check the problem here. It says :

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.

Thought Process – If you take a look at this problem you’ll observe that only numbers that are multiples of 3 and 5 are – 3, 5,6,9. You have to repeat this process for 1000 numbers in your program. Yes, you guessed it right we’re going to use loop in our program. We’re going to run a loop that counts upto 1000. We also need to check for the condition that checks the number is divisble by 3 and 5 and remainder is 0. In such case we’re going to use if condition inside our for loop to filter those numbers and it in our another variable that keep the sum.

You can see this in action in following code:

Code

<?php
$j=0;
$k=0;
for($j=1;$j<=1000;$j++)
{
    if($j%3==0 ||$j%5==0)
    $k+=$j;
}
echo "The sum of Multiples of 3 and 5 is: ",$k;
?>

This is very simple problem and I guess you should attempt it as much as possible before looking at this site for answer. If you manage to learn it in php, try to impement the logic in python or C# or C++. This will improve your language learning and logic too.

Loops always check for the particular condition before executing particular task. If the condition is true or false, it’ll generate the output for the loop.

While Loop

Let’s start learning with ‘while’ loop first. Check the basic syntax of the while loop:

Code

<?php
 
while(condition)
{
}
?>

You’ve to place some condition in order to execute while loop. If your condition evalutes to true, the loop will execute or lese it’ll not.

<?php
$i=1;
while ($i<=10)
{
echo $i;
echo '<br/>';
$i++;
}
?>

For Loop

For loop allows you to have control over initiation, condition and increment in the same line. Like while loop it also processes a block of code until a statement becomes false.

Syntax Code:

<?php
for (condition)
{
}
?>

In this code our condition statement contains – initiation, condition and increment. You can skip increment if you want to use it inside the block of code. Either way with increment is fine with for loop. Check the modification in code made for – “for loop”.

<?php
for($=1;$i<=10;$i++)
{
echo $i;
echo '<br/>';
$i++;
}
?>

FOREACH Loop

A foreach loop is used when you’re dealing with arrays. It executes a block of code as long as loop uses all the values of arrays specified in the condition are used. Once those values are used then loop ends. So there is no need to explicitly add the increment for the arrays.

Syntax

<?php
$i=array();
foreach($i as $j)
{
}
?>

In this loop, we’re creating an array to be used foreach loop. This array specifies a particular set of values upto which the loop will execute.

<?php
$i=array(1,2,3,4,5);
foreach($i as $k)
{
echo $k;
echo '<br/>';
}
?>

As you can see in the output, this loop executes till all the values in array are used. Once used you can see that loop ends.

These three are the types of loops that you’re going to use while programming in php. Hope this tutorial helps to you and if you have any suggestion or feedback on these tutorials, feel free to let us know.

PHP redirects being a server side script works on all browsers and you don’t have to worry about browser standards. Redirection is quick and distraction free as you’re not wasting time by showing them some demo page in between the redirection. In this tutorial we’re assuming that you’re creating redirection on your 404 page. You can use the following code to redirect search engines and users to homepage.

Code:

<?php
header('Location:http://yahoo.com');
?>

You can replace the yahoo with some other page of your site. You can also use specific 404 page or archive page which most of the websites use to redirect users. Archive page or sitemap pages are more useful as they let visitors make decision about where to visit next from the redirected page.

Note: While running this php page make sure you’re not placing this code in < body > tag. Make this page purely php page without any other code in between and before or after the code. This should be the only code that needs to be executed in order for this example to work. If you’re using php designer 7 onwards then you may notice that redirection example may not work in the IDE. For some strange reasons it doesn’t work inside IDE.

In this tutorial we’ll see how to disable the the right click browser specific menu. As this JavaScript is taken from dynamic drive, credit of this code snippet goes to renigade (dynamic drive).

Disable Right Click on Static HTML Sites

For static sites with limited web pages should add the following code inside the html page. Make sure you add this code before < / body > tag of the html page.

<script language=JavaScript>
<!--
var message="";
///////////////////////////////////
function clickIE() {if (document.all) {(message);return false;}}
function clickNS(e) {if 
(document.layers||(document.getElementById&&!document.all)) {
if (e.which==2||e.which==3) {(message);return false;}}}
if (document.layers) 
{document.captureEvents(Event.MOUSEDOWN);document.onmousedown=clickNS;}
else{document.onmouseup=clickNS;document.oncontextmenu=clickIE;}
 
document.oncontextmenu=new Function("return false")
// --> 
</script>

Disable Right Click on WordPress Blog

In case of wordpress you can either edit header.php or footer.php of your theme OR you can use text widget in sidebar or footer to add this code. If you change theme, just add the widget back again to enable the script or else you can again modify the footer.php or header.php of theme.

Adding Javascript Code in Text Widget of WordPress

Disable Right Click on Blogger Blog

You can add HTML widget in sidebar and then add the above code. This will eliminate the need to updating the code if you change theme. This sidebar usually remains consistent even after theme changes so you’ll definitely benefit by adding the code in html widget.

Tumblr, WordPress.com, Joomla and Drupal

• WordPress.com allows you to use add TEXT widget in sidebar which you can use to add this javascript snippet.
• Tumblr is an online CMS and in order to make the changes you have to edit the theme of tumblr. So after every theme changes you have to add this javascript snippet into theme.
• Joomla and Drupal has theme and templates feature which you can use to edit the themes. Adding this javascript snippet in your theme is very easy if you’re already using such a complicated CMS like drupal (or joomla).

If you’re using any other content management system like textpattern, expression engine etc. then you have to ask for help in respective community forums.

In this tutorial we’re going to take a look at function syntax and various ways to use functions.

Syntax

<?php
function name_of_function() {
 }
?>

You can follow camel-case convention for the function name. You can also use underscore for the function name but never start it with number or else compiler will flag error.

Keep these points in mind while writing functions -

• Start your function with the keyword function.
• Function should be declared first before using in your program.
• Make sure the function name is correctly used in a program.

How to Use PHP function

We have already created our first function so let’s take a quick look at how we can use it in our program. One thing to note that you have to declare the function before you use it. You can also add the function by import function if you want in your program.

<?php
function hello(){
echo "hello";
}
echo "this is function demo";
echo "<br/>";
hello();
?>

Parametrized Functions

You can pass value to your functions from outside the functions. You can then use the value to process in your function or just use them to print out on web page.

<?php 
function apple($num){
echo "no of apples are". $num . "<br/>";
}
apple(12);
?>

You can also process the value and show results back to the user.

<?php
function apple($num){
$num+=1;
echo "no of apples after adding 1 more in the basket :". $num ."<br/>";
}
apple(12);
?>

That’s it. You now know how to use functions in php. You can practice using functions with some demo programs. There are many home work assignments out there that you can see for more php function examples. Hope this helps you. Feel free to ask questions, suggest a feature, point errors. Don’t forget to bookmark or share this site in any social network site of your choice.

In this tutorial we’re going to create a page that passes two variables to another page via forms. Variables “toys” and “game” are the ones we’re going to pass.We’re going to add these in the form of attributes in the form. These two variables will be displaying a value that user selects in first page. Let’s create a simple HTML form with some options -

<html>
<body>
<h3>Select an Option</h4>
<form action="toys.php" method="post">
<select name="game">
<option>kite</option>
<option>yo yo</option>
<option>beyblade</option>
</select>
How many : <input name="toys" type="text"/>
<input type="submit"/>
</form>
</body>
</html>

If you read the code carefully then you’ll notice that field name “game” and “toys” are going to be important here. As they’re the items that we’re going to pass to other page.

Code toys.php

<html>
<body>
<?php 
$toys=$_post['toys'];
$game=$_post['game'];
echo "You want".toys." ".$game.";
</body>
</html>

You can upload these two files on your webserver and execute it to see if they’re showing you the right output. You can test this on your own if you have xampp server on your desktop.