Unset() function means in php?

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The behavior of unset()  inside of a function can vary depending on what type of variable you are attempting to destroy. If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset()  was called. Example <?php function destroy_foo() { global $foo; unset($foo); } $foo = 'bar'; destroy_foo(); echo $foo; ?>
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Multiple inheritance in PHP?

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Inheritance is a well-established programming principle, and PHP makes use of this principle in its object model. This principle will affect the way many classes and objects relate to one another. For example, when you extend a class, the subclass inherits all of the public and protected methods from the parent class. Unless a class overrides those methods, they will retain their original functionality. This is useful for defining and abstracting functionality, and permits the implementation of additional functionality in similar objects without the need to reimplement all of the shared functionality. Example <?php class Foo { public function printItem($string) { echo 'Foo: ' . $string . PHP_EOL; } public function printPHP() { echo 'PHP is great.' . PHP_EOL; } } class Bar extends Foo { public function printItem($string) { echo 'Bar: ' . $string . PHP_EOL; } } $foo = new Foo(); $bar = new Bar(); $foo->printItem('baz'); // Output: 'Foo: baz' $foo->printPHP();       // Output: 'PHP is great' $bar->printItem('baz'); // Output: 'Bar: baz' $bar->printPHP();       // Output: 'PHP is great' ?>
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Data Sending Ways in PHP

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There are some certain ways to send your information or data to the PHP page- Using Form Methods - Get & Post Using Cookies & Session Using Query String / URL Rewriting Using Hidden form fieldForm MethodsThe GET Method: The GET method sends information separated by the ? Operator.Example: http://www.xyz.com/home.html?city=Gurgaon Please note that the GET method is restricted to send upto 1024 characters (1024 bytes) only. You should not use GET method if you have password or other confidential information to be proceeding over the server. GET can't be used to send binary data, like images or word documents, to the server. The PHP provides $_GET associative array or super global variable to access the data sent using GET method. The POST Method The POST method transfers information via HTTP…
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Error Handling in PHP

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Error handling is the process of catching errors from the program and then taking appropriate action. Before proceeding for error handling you should get to know how many types of errors occurred in PHP. Notices: These are non-critical errors that occurred while executing a script - for example, accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all - although, as you will see, you can change this default behavior. Warnings: These are more serious errors - for example, attempting to use a file (using include() method) which does not exist. By default, these errors are displayed to the user, but they do not result in script termination. Fatal Errors: These are critical errors - for example, creating an…
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Working with Images – PHP

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We need to create an HTML form that allows you to choose the file to be uploaded. Note: please make sure you have form method type is post and enctype=”mutipart/form-data” to to handle file uploading process successfully. HTML Code <form enctype="multipart/form-data" action="process.php" method="POST"> Choose File : <input name="myfile" type="file" /> <input type="submit" value="Upload" /> </form> Now create a PHP file process.php for handling file information <?php // get the uploaded file name $filename= $_FILES['myfile'][‘name’]; // get the file type $filetype= $_FILES['myfile'][‘type’]; // get the file size (in bytes) $filesize= $_FILES['myfile'][‘size’]; // You may put your validations here i.e restrict file size if($filesize>=1000000) { echo “ File is too Large, Maximum file size should be 1 MB”; exit; } // Validation to check if uploaded file is an Image if($filetype !=”image/jpeg”…
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Require () and Include () function in PHP

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The Include() and require() statements are used to insert codes written in other files, in the flow of  execution. The main of using include and require functions to integrate one page code or content into another page. You can maintain usually some repeated functionality in the form of PHP file and finally you can call it wherever you want. See, the following example demonstrates how to integrate a menu content in other pages of PHP. There is a page in menu.php and it can be included in some other pages of the website. Menu.php <a href=”index.php”>Home</a> <a href=”services.php”>Services</a> <a href=”about.php”>About Us</a> <a href=”contact.php”>Contact Us</a> The following page index.php uses above menu.php content. See the below code how it follows <head> <title>My Web page</title> </head> <body> <?php include  “menu.php “; ?> </body> Difference between Include…
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The do-while loop

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Difference Between while and do…while Loop: With a while loop, the condition to be evaluated is tested at the beginning of each loop statement, so if the conditional expression evaluates to false, the loop will never be executed. With a do-while loop, on the other hand, the loop will always be executed once, even if the conditional expression is false, because the condition is evaluated at the end of the loop statement. Example: <?php $i = 1; do { $i++; echo  $i . "<br>"; } while($i <= 3); ?>  Output: 2 3 4
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PHP -Building Blocks

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If –else statements: if…else statement – executes set of codes if a condition is true and another code if the condition is false Within a statement, if a certain condition is true, then something happens. Otherwise, something else happens. We can continue adding else statements as many times as we need. So, within PHP statement, we first define the variable and then set up the conditional statements like this: Syntax: if (condition) code to be executed if condition is true; elseif (condition) code to be executed if condition is true; else code to be executed if condition is false; Example 1: <?php $avg = 50 if ($avg>60) { echo "You have a good score"; } else { echo "Score is less than average"; } ?> Example 2:  <?php $status =…
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