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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PHP – Strings Functions

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String functions are the most important functions frequently used in PHP. String is the sequence of characters, like "Let’s learn String functions”. There is no installation required to use string function. Example <?php $name = "Hirdesh Bhardwaj"; print($name); ?> String Concatenation Operator To concatenate two string variables together, we use the dot (.) operator − <?php $txt1="Hello Readers"; $txt2="8756"; echo $txt1 . " " . $txt2; ?> Using the strlen() function The strlen() function is used to get the length of a string. <?php $txt=”Webs Jyoti”; echo strlen($txt); ?> This will produce the following result – 10 (including space) Using the strpos() function The strpos() function is used to search for a text or character within a string. If the value is found then this will return the position of…
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OOPs Concepts – PHP

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OOP is intimidating to a lot of developers because it introduces new syntax and, at a glance, appears to be far more complex than simple procedural, or inline, code. However, upon closer inspection, OOP is actually a very straightforward and ultimately simpler approach to programming. Before we go in details, let’s define important terms related to Object Oriented Programming. Class− Simply Class is a collection of member variables and its functions. Object−You define a class once and then make many objects that belong to it. Objects have state behavior and identity. Member functions and Variables− these are the functions and variables defined inside a class and are used to access object data. Inheritance– Simply creating a new class from the existing class. When a class is defined by inheriting existing…
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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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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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The For Loop

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PHP for loop can be used to traverse set of code for the specified number of times. For example if you want to repeat something ten or twenty times. It should be used if number of iteration is known otherwise I recommend you to use while loop. Syntax: for (Initialization; Condition; Progressive) { //set of statements to be executed; } Parameters: Initialization: Initialize the loop counter value Condition: Check for condition. If it evaluates to TRUE, the loop continues. If FALSE then the loop ends. Progressive: Increase / Decrease the loop counter value Example: for($var=1; $var<=20; $var=$var+1) { echo $var ." "; } Output: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Example: to display 1st 20 natural…
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PHP Superglobals

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We already learned about variables, but there are some Readymade or predefined keywords in PHP that can be used without you having to create them first. Predefined or Superglobals variables are used to provide information from and about the web server, the web browser, and the user. There are several types of Super Global Variables:- $_GET - Is used to pass data through URL. Example: http://websjyoti.com?id=2 $_POST - Is used to pass data to server by hiding from URL. $_REQUEST – Is the combination of $_GET, $_POST, and $_COOKIE. $_SESSION - is used to maintain session and data from Local machine to Server. $_COOKIE – Is used to save/get user data on same machine in browser cookies. $_SERVER – Is an associative array which is used to know server information…
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