Thursday, August 31, 2017

Explain about AngularJS Arrays.


AngularJS Arrays

AngularJS arrays are like JavaScript arrays:

Example

<div ng-app="" ng-init="points=[1,15,19,2,40]">

<p>The third result is {{ points[2] }}</p>

</div>
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Do you know about AngularJS Objects?

AngularJS Objects

AngularJS objects are like JavaScript objects:

Example

<div ng-app="" ng-init="person={firstName:'John',lastName:'Doe'}">

<p>The name is {{ person.lastName }}</p>

</div>
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Show the structure of AngularJS Strings.

AngularJS Strings

AngularJS strings are like JavaScript strings:

Example

<div ng-app="" ng-init="firstName='John';lastName='Doe'">

<p>The name is {{ firstName + " " + lastName }}</p>

</div>
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What is AngularJS Numbers?

AngularJS Numbers

AngularJS numbers are like JavaScript numbers:

Example

<div ng-app="" ng-init="quantity=1;cost=5">

<p>Total in dollar: {{ quantity * cost }}</p>

</div>
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Explai about AngularJS expressions.

AngularJS Expressions

AngularJS expressions can be written inside double braces: {{ expression }}.
AngularJS expressions can also be written inside a directive: ng-bind="expression".
AngularJS will resolve the expression, and return the result exactly where the expression is written.
AngularJS expressions are much like JavaScript expressions: They can contain literals, operators, and variables.
Example {{ 5 + 5 }} or {{ firstName + " " + lastName }}

Example

<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<body>

<div ng-app="">
  <p>My first expression: {{ 5 + 5 }}</p>
</div>

</body>
</html>
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What does AngularJS controller do ?

AngularJS controllers control applications:

AngularJS Controller

app.controller('myCtrl', function($scope) {
    $scope.firstName= "John";
    $scope.lastName= "Doe";
});
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What do AngularJS modules define?

AngularJS modules define applications:

AngularJS Module

var app = angular.module('myApp', []);
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Show about AngularJS applications.

AngularJS Applications

AngularJS modules define AngularJS applications.
AngularJS controllers control AngularJS applications.
The ng-app directive defines the application, the ng-controller directive defines the controller.

AngularJS Example

<div ng-app="myApp" ng-controller="myCtrl">

First Name: <input type="text" ng-model="firstName"><br>
Last Name: <input type="text" ng-model="lastName"><br>
<br>
Full Name: {{firstName + " " + lastName}}

</div>

<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
    $scope.firstName= "John";
    $scope.lastName= "Doe";
});</script>
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Describe about AngularJS Expressions.

AngularJS Expressions

AngularJS expressions are written inside double braces: {{ expression }}.
AngularJS will "output" data exactly where the expression is written:

AngularJS Example

<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<body>

<div ng-app="">
  <p>My first expression: {{ 5 + 5 }}</p>
</div>

</body>
</html>
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Does AngularJSextend HTML?

AngularJS Extends HTML

AngularJS extends HTML with ng-directives.
The ng-app directive defines an AngularJS application.
The ng-model directive binds the value of HTML controls (input, select, textarea) to application data.
The ng-bind directive binds application data to the HTML view.
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Is AngularJS a JavaScript Framework?

AngularJS is a JavaScript Framework

AngularJS is a JavaScript framework. It is a library written in JavaScript.
AngularJS is distributed as a JavaScript file, and can be added to a web page with a script tag:
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
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Who started to work with AngularJS?

Miško Hevery, a Google employee, started to work with AngularJS in 2009.
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What Should you know before AngularJS?

What You Should Already Know

Before you study AngularJS, you should have a basic understanding of:
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Show the AngularJS Example.

AngularJS Example

<!DOCTYPE html>
<html lang="en-US">
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<body>

<div ng-app="">
  <p>Name : <input type="text" ng-model="name"></p>
  <h1>Hello {{name}}</h1>
</div>

</body>
</html>
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Write down the Usage of AngularJS?

 Usage of

AngularJS


First, you will learn the basics of AngularJS: directives, expressions, filters, modules, and controllers.
Then you will learn everything else you need to know about AngularJS:
Events, DOM, Forms, Input, Validation, Http, and more.
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what is AngularJS?


AngularJS

AngularJS extends HTML with new attributes.
AngularJS is perfect for Single Page Applications (SPAs).
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Wednesday, August 23, 2017

Describe about PHP - Validate URL.

PHP - Validate URL

The code below shows a way to check if a URL address syntax is valid (this regular expression also allows dashes in the URL). If the URL address syntax is not valid, then store an error message:
$website = test_input($_POST["website"]);
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
  $websiteErr = "Invalid URL";
}
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Show the structure of PHP - Validate Name, E-mail, and URL.

PHP - Validate Name, E-mail, and URL

Now, the script looks like this:

Example

<?php
// define variables and set to empty values$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
  if (empty($_POST["name"])) {
    $nameErr = "Name is required";
  } else {
    $name = test_input($_POST["name"]);
    // check if name only contains letters and whitespace    if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
      $nameErr = "Only letters and white space allowed";
    }
  }

  if (empty($_POST["email"])) {
    $emailErr = "Email is required";
  } else {
    $email = test_input($_POST["email"]);
    // check if e-mail address is well-formed    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
      $emailErr = "Invalid email format";
    }
  }

  if (empty($_POST["website"])) {
    $website = "";
  } else {
    $website = test_input($_POST["website"]);
    // check if URL address syntax is valid (this regular expression also allows dashes in the URL)    if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
      $websiteErr = "Invalid URL";
    }
  }

  if (empty($_POST["comment"])) {
    $comment = "";
  } else {
    $comment = test_input($_POST["comment"]);
  }

  if (empty($_POST["gender"])) {
    $genderErr = "Gender is required";
  } else {
    $gender = test_input($_POST["gender"]);
  }
}
?>
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Explain about PHP - Validate Name.

PHP - Validate Name

The code below shows a simple way to check if the name field only contains letters and whitespace. If the value of the name field is not valid, then store an error message:
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
  $nameErr = "Only letters and white space allowed";
}
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shows how to make input fields required and create error messages

This chapter shows how to make input fields required and create error messages if needed.

PHP - Required Fields

From the validation rules table on the previous page, we see that the "Name", "E-mail", and "Gender" fields are required. These fields cannot be empty and must be filled out in the HTML form.
Field Validation Rules
Name Required. + Must only contain letters and whitespace
E-mail Required. + Must contain a valid email address (with @ and .)
Website Optional. If present, it must contain a valid URL
Comment Optional. Multi-line input field (textarea)
Gender Required. Must select one
In the previous chapter, all input fields were optional.
In the following code we have added some new variables: $nameErr, $emailErr, $genderErr, and $websiteErr. These error variables will hold error messages for the required fields. We have also added an if else statement for each $_POST variable. This checks if the $_POST variable is empty (with the PHP empty() function). If it is empty, an error message is stored in the different error variables, and if it is not empty, it sends the user input data through the test_input() function:
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
  if (empty($_POST["name"])) {
    $nameErr = "Name is required";
  } else {
    $name = test_input($_POST["name"]);
  }

  if (empty($_POST["email"])) {
    $emailErr = "Email is required";
  } else {
    $email = test_input($_POST["email"]);
  }

  if (empty($_POST["website"])) {
    $website = "";
  } else {
    $website = test_input($_POST["website"]);
  }

  if (empty($_POST["comment"])) {
    $comment = "";
  } else {
    $comment = test_input($_POST["comment"]);
  }

  if (empty($_POST["gender"])) {
    $genderErr = "Gender is required";
  } else {
    $gender = test_input($_POST["gender"]);
  }
}
?>

PHP - Display The Error Messages

Then in the HTML form, we add a little script after each required field, which generates the correct error message if needed (that is if the user tries to submit the form without filling out the required fields):

Example

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">

Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail:
<input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website:
<input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">

</form>
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Show some new added variables.

<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
  if (empty($_POST["name"])) {
    $nameErr = "Name is required";
  } else {
    $name = test_input($_POST["name"]);
  }

  if (empty($_POST["email"])) {
    $emailErr = "Email is required";
  } else {
    $email = test_input($_POST["email"]);
  }

  if (empty($_POST["website"])) {
    $website = "";
  } else {
    $website = test_input($_POST["website"]);
  }

  if (empty($_POST["comment"])) {
    $comment = "";
  } else {
    $comment = test_input($_POST["comment"]);
  }

  if (empty($_POST["gender"])) {
    $genderErr = "Gender is required";
  } else {
    $gender = test_input($_POST["gender"]);
  }
}
?>
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Explain the PHP - Required Fields .

PHP - Required Fields

From the validation rules table on the previous page, we see that the "Name", "E-mail", and "Gender" fields are required. These fields cannot be empty and must be filled out in the HTML form.
Field Validation Rules
Name Required. + Must only contain letters and whitespace
E-mail Required. + Must contain a valid email address (with @ and .)
Website Optional. If present, it must contain a valid URL
Comment Optional. Multi-line input field (textarea)
Gender Required. Must select one
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Saturday, August 19, 2017

How to write down a A Simple HTML Form?

PHP - A Simple HTML Form

The example below displays a simple HTML form with two input fields and a submit button:

Example

<html>
<body>

<form action="welcome.php" method="post">
Name: <input type="text" name="name"><br>
E-mail: <input type="text" name="email"><br>
<input type="submit">
</form>

</body>
</html>
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show the code in "test_get.php.

The example below shows the code in "test_get.php":

Example

<html>
<body>

<?php
echo "Study " . $_GET['subject'] . " at " . $_GET['web'];
?>

</body>
</html>
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Show a structure of a PHP $_POST.

PHP $_POST

PHP $_POST is widely used to collect form data after submitting an HTML form with method="post". $_POST is also widely used to pass variables.
The example below shows a form with an input field and a submit button. When a user submits the data by clicking on "Submit", the form data is sent to the file specified in the action attribute of the <form> tag. In this example, we point to the file itself for processing form data. If you wish to use another PHP file to process form data, replace that with the filename of your choice. Then, we can use the super global variable $_POST to collect the value of the input field:

Example

<html>
<body>

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
  Name: <input type="text" name="fname">
  <input type="submit">
</form>

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // collect value of input field    $name = $_POST['fname'];
    if (empty($name)) {
        echo "Name is empty";
    } else {
        echo $name;
    }
}
?>

</body>
</html>
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Make a strucrure of PHP $_REQUEST.

PHP $_REQUEST

PHP $_REQUEST is used to collect data after submitting an HTML form.
The example below shows a form with an input field and a submit button. When a user submits the data by clicking on "Submit", the form data is sent to the file specified in the action attribute of the <form> tag. In this example, we point to this file itself for processing form data. If you wish to use another PHP file to process form data, replace that with the filename of your choice. Then, we can use the super global variable $_REQUEST to collect the value of the input field:

Example

<html>
<body>

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
  Name: <input type="text" name="fname">
  <input type="submit">
</form>

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // collect value of input field    $name = $_REQUEST['fname'];
    if (empty($name)) {
        echo "Name is empty";
    } else {
        echo $name;
    }
}
?>

</body>
</html>
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What are the most important elements that can go inside $_SERVER


The following table lists the most important elements that can go inside $_SERVER:
Element/Code Description
$_SERVER['PHP_SELF'] Returns the filename of the currently executing script
$_SERVER['GATEWAY_INTERFACE'] Returns the version of the Common Gateway Interface (CGI) the server is using
$_SERVER['SERVER_ADDR'] Returns the IP address of the host server
$_SERVER['SERVER_NAME'] Returns the name of the host server (such as www.w3schools.com)
$_SERVER['SERVER_SOFTWARE'] Returns the server identification string (such as Apache/2.2.24)
$_SERVER['SERVER_PROTOCOL'] Returns the name and revision of the information protocol (such as HTTP/1.1)
$_SERVER['REQUEST_METHOD'] Returns the request method used to access the page (such as POST)
$_SERVER['REQUEST_TIME'] Returns the timestamp of the start of the request (such as 1377687496)
$_SERVER['QUERY_STRING'] Returns the query string if the page is accessed via a query string
$_SERVER['HTTP_ACCEPT'] Returns the Accept header from the current request
$_SERVER['HTTP_ACCEPT_CHARSET'] Returns the Accept_Charset header from the current request (such as utf-8,ISO-8859-1)
$_SERVER['HTTP_HOST'] Returns the Host header from the current request
$_SERVER['HTTP_REFERER'] Returns the complete URL of the current page (not reliable because not all user-agents support it)
$_SERVER['HTTPS'] Is the script queried through a secure HTTP protocol
$_SERVER['REMOTE_ADDR'] Returns the IP address from where the user is viewing the current page
$_SERVER['REMOTE_HOST'] Returns the Host name from where the user is viewing the current page
$_SERVER['REMOTE_PORT'] Returns the port being used on the user's machine to communicate with the web server
$_SERVER['SCRIPT_FILENAME'] Returns the absolute pathname of the currently executing script
$_SERVER['SERVER_ADMIN'] Returns the value given to the SERVER_ADMIN directive in the web server configuration file (if your script runs on a virtual host, it will be the value defined for that virtual host) (such as someone@w3schools.com)
$_SERVER['SERVER_PORT'] Returns the port on the server machine being used by the web server for communication (such as 80)
$_SERVER['SERVER_SIGNATURE'] Returns the server version and virtual host name which are added to server-generated pages
$_SERVER['PATH_TRANSLATED'] Returns the file system based path to the current script
$_SERVER['SCRIPT_NAME'] Returns the path of the current script
$_SERVER['SCRIPT_URI'] Returns the URI of the current page
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How to use some of the elements in $_SERVER?

PHP $_SERVER

$_SERVER is a PHP super global variable which holds information about headers, paths, and script locations.
The example below shows how to use some of the elements in $_SERVER:

Example

<?php
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
echo $_SERVER['HTTP_HOST'];
echo "<br>";
echo $_SERVER['HTTP_REFERER'];
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME'];
?>
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How to use the super global variable $GLOBALS?

The example below shows how to use the super global variable $GLOBALS:

Example

<?php
$x = 75;
$y = 25;

function addition() {
    $GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y'];
}

addition();
echo $z;
?>
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Make a list of The PHP superglobal variables?

The PHP superglobal variables are:
  • $GLOBALS
  • $_SERVER
  • $_REQUEST
  • $_POST
  • $_GET
  • $_FILES
  • $_ENV
  • $_COOKIE
  • $_SESSION
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What are the Superglobals ?

Superglobals were introduced in PHP 4.1.0, and are built-in variables that are always available in all scopes.
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What are the PHP - Sort Functions For Arrays?

  • PHP - Sort Functions For Arrays

     
  • sort() - sort arrays in ascending order
  • rsort() - sort arrays in descending order
  • asort() - sort associative arrays in ascending order, according to the value
  • ksort() - sort associative arrays in ascending order, according to the key
  • arsort() - sort associative arrays in descending order, according to the value
  • krsort() - sort associative arrays in descending order, according to the key
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Friday, August 18, 2017

How many types of objects?

There are 3 types of objects:
  • Object
  • Date
  • Array
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How many different data types?

In JavaScript there are 5 different data types that can contain values:
  • string
  • number
  • boolean
  • object
  • function
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Saturday, August 12, 2017

Can you explain about PHP Increment / Decrement Operators?

PHP Increment / Decrement Operators

The PHP increment operators are used to increment a variable's value.
The PHP decrement operators are used to decrement a variable's value.
Operator Name Description Show it
++$x Pre-increment Increments $x by one, then returns $x
$x++ Post-increment Returns $x, then increments $x by one
--$x Pre-decrement Decrements $x by one, then returns $x
$x-- Post-decrement Returns $x, then decrements $x by one
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Explain about PHP Comparison Operators.

PHP Comparison Operators

The PHP comparison operators are used to compare two values (number or string):
Operator Name Example Result Show it
== Equal $x == $y Returns true if $x is equal to $y
=== Identical $x === $y Returns true if $x is equal to $y, and they are of the same type
!= Not equal $x != $y Returns true if $x is not equal to $y
<> Not equal $x <> $y Returns true if $x is not equal to $y
!== Not identical $x !== $y Returns true if $x is not equal to $y, or they are not of the same type
> Greater than $x > $y Returns true if $x is greater than $y
< Less than $x < $y Returns true if $x is less than $y
>= Greater than or equal to $x >= $y Returns true if $x is greater than or equal to $y
<= Less than or equal to $x <= $y Returns true if $x is less than or equal to $y
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Do you know about PHP Assignment Operators?

PHP Assignment Operators

The PHP assignment operators are used with numeric values to write a value to a variable.
The basic assignment operator in PHP is "=". It means that the left operand gets set to the value of the assignment expression on the right.
Assignment Same as... Description
x = y x = y The left operand gets set to the value of the expression on the right
x += y x = x + y Addition
x -= y x = x - y Subtraction
x *= y x = x * y Multiplication
x /= y x = x / y Division
x %= y x = x % y Modulus
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Define about PHP Arithmetic Operators.

PHP Arithmetic Operators

The PHP arithmetic operators are used with numeric values to perform common arithmetical operations, such as addition, subtraction, multiplication etc.
Operator Name Example Result Show it
+ Addition $x + $y Sum of $x and $y
- Subtraction $x - $y Difference of $x and $y
* Multiplication $x * $y Product of $x and $y
/ Division $x / $y Quotient of $x and $y
% Modulus $x % $y Remainder of $x divided by $y
** Exponentiation $x ** $y Result of raising $x to the $y'th power (Introduced in PHP 5.6)
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What are the PHP operators ?

PHP divides the operators in the following groups:
  • Arithmetic operators
  • Assignment operators
  • Comparison operators
  • Increment/Decrement operators
  • Logical operators
  • String operators
  • Array operators
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Wednesday, August 9, 2017

How to create a PHP Constant?

Create a PHP Constant

To create a constant, use the define() function.

Syntax

define(name, value, case-insensitive)
Parameters:
  • name: Specifies the name of the constant
  • value: Specifies the value of the constant
  • case-insensitive: Specifies whether the constant name should be case-insensitive. Default is false
The example below creates a constant with a case-sensitive name:

Example

<?php
define("GREETING", "Welcome to W3Schools.com!");
echo GREETING;
?>
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Do you know PHP Array?

PHP Array

An array stores multiple values in one single variable.
In the following example $cars is an array. The PHP var_dump() function returns the data type and value:

Example

<?php
$cars = array("Volvo","BMW","Toyota");
var_dump($cars);
?>
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WHAT DO YOU KNOW PHP Boolean?

PHP Boolean

A Boolean represents two possible states: TRUE or FALSE.
$x = true;
$y = false;
Booleans are often used in conditional testing. You will learn more about conditional testing in a later chapter of this tutorial.
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Explain about PHP Float.

PHP Float

A float (floating point number) is a number with a decimal point or a number in exponential form.
In the following example $x is a float. The PHP var_dump() function returns the data type and value:

Example

<?php
$x = 10.365;
var_dump($x);
?>
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Explain about PHP Integer.

PHP Integer

An integer data type is a non-decimal number between -2,147,483,648 and 2,147,483,647.
Rules for integers:
  • An integer must have at least one digit
  • An integer must not have a decimal point
  • An integer can be either positive or negative
  • Integers can be specified in three formats: decimal (10-based), hexadecimal (16-based - prefixed with 0x) or octal (8-based - prefixed with 0)
In the following example $x is an integer. The PHP var_dump() function returns the data type and value:

Example

<?php
$x = 5985;
var_dump($x);
?>
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What is PHP String

PHP String

A string is a sequence of characters, like "Hello world!".
A string can be any text inside quotes.

Example

<?php
$x = "Hello world!";
$y = 'Hello world!';

echo $x;
echo "<br>";
echo $y;
?>
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Which data type does PHP support?

PHP supports the following data types:
  • String
  • Integer
  • Float (floating point numbers - also called double)
  • Boolean
  • Array
  • Object
  • NULL
  • Resource
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Describe about PHP echo and print Statements

PHP echo and print Statements

echo and print are more or less the same. They are both used to output data to the screen.
The differences are small: echo has no return value while print has a return value of 1 so it can be used in expressions. echo can take multiple parameters (although such usage is rare) while print can take one argument. echo is marginally faster than print.
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How to output text and variables with the print statement?

The following example shows how to output text and variables with the print statement:

Example

<?php
$txt1 = "Learn PHP";
$txt2 = "W3Schools.com";
$x = 5;
$y = 4;

print "<h2>$txt1</h2>";
print "Study PHP at $txt2<br>";
print $x + $y;
?>
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Do you know about the PHP print Statement?

The PHP print Statement

The print statement can be used with or without parentheses: print or print().
Display Text
The following example shows how to output text with the print command (notice that the text can contain HTML markup):

Example

<?php
print "<h2>PHP is Fun!</h2>";
print "Hello world!<br>";
print "I'm about to learn PHP!";
?>
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Sunday, August 6, 2017

Describe about PHP The global Keyword.

PHP The global Keyword

The global keyword is used to access a global variable from within a function.
To do this, use the global keyword before the variables (inside the function):

Example

<?php
$x = 5;
$y = 10;

function myTest() {
    global $x, $y;
    $y = $x + $y;
}

myTest();
echo $y; // outputs 15 ?>
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What is a variable declared?

A variable declared within a function has a LOCAL SCOPE and can only be accessed within that function
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Describe about global and local scope.

Global and Local Scope

A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a function:

Example

<?php
$x = 5; // global scope
function myTest() {
    // using x inside this function will generate an error    echo "<p>Variable x inside function is: $x</p>";
}
myTest();

echo "<p>Variable x outside function is: $x</p>";
?>
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What is PHP Variables Scope/

The scope of a variable is the part of the script where the variable can be referenced/used.
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How many variable scopes of PHP?

PHP has three different variable scopes:
  • local
  • global
  • static
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Friday, August 4, 2017

Give an example of Output Variables.

Output Variables

The PHP echo statement is often used to output data to the screen.
The following example will show how to output text and a variable:

Example

<?php
$txt = "W3Schools.com";
echo "I love $txt!";
?>
The following example will produce the same output as the example above:

Example

<?php
$txt = "W3Schools.com";
echo "I love " . $txt . "!";
?>
 
 
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Describe about PHP Variables.

PHP Variables

A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume).
Rules for PHP variables:
  • A variable starts with the $ sign, followed by the name of the variable
  • A variable name must start with a letter or the underscore character
  • A variable name cannot start with a number
  • A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
  • Variable names are case-sensitive ($age and $AGE are two different variables)
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How to Create PHP Variables?

Creating (Declaring) PHP Variables

In PHP, a variable starts with the $ sign, followed by the name of the variable:

Example

<?php
$txt = "Hello world!";
$x = 5;
$y = 10.5;
?>
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Thursday, August 3, 2017

How to show the first statement will display/

In the example below, only the first statement will display the value of the $color variable (this is because $color, $COLOR, and $coLOR are treated as three different variables):

Example

<!DOCTYPE html>
<html>
<body>

<?php
$color = "red";
echo "My car is " . $color . "<br>";
echo "My house is " . $COLOR . "<br>";
echo "My boat is " . $coLOR . "<br>";
?>

</body>
</html>
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Give an example of PHP Case Sensitivity.

PHP Case Sensitivity

In PHP, all keywords (e.g. if, else, while, echo, etc.), classes, functions, and user-defined functions are NOT case-sensitive.
In the example below, all three echo statements below are legal (and equal):

Example

<!DOCTYPE html>
<html>
<body>

<?php
ECHO "Hello World!<br>";
echo "Hello World!<br>";
EcHo "Hello World!<br>";
?>

</body>
</html>
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Explain about Comments in PHP.

Comments in PHP

A comment in PHP code is a line that is not read/executed as part of the program. Its only purpose is to be read by someone who is looking at the code.
Comments can be used to:
  • Let others understand what you are doing
  • Remind yourself of what you did - Most programmers have experienced coming back to their own work a year or two later and having to re-figure out what they did. Comments can remind you of what you were thinking when you wrote the code
PHP supports several ways of commenting:

Example

<!DOCTYPE html>
<html>
<body>

<?php
// This is a single-line comment
# This is also a single-line comment
/*
This is a multiple-lines comment block
that spans over multiple
lines
*/

// You can also use comments to leave out parts of a code line$x = 5 /* + 15 */ + 5;
echo $x;
?>
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Describe about Basic PHP Syntax.

Basic PHP Syntax

A PHP script can be placed anywhere in the document.
A PHP script starts with <?php and ends with ?>:
<?php
// PHP code goes here
?>
The default file extension for PHP files is ".php".
A PHP file normally contains HTML tags, and some PHP scripting code.
Below, we have an example of a simple PHP file, with a PHP script that uses a built-in PHP function "echo" to output the text "Hello World!" on a web page:

Example

<!DOCTYPE html>
<html>
<body>

<h1>My first PHP page</h1>

<?php
echo "Hello World!";
?>

</body>
</html>
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What is a PHP script?

A PHP script is executed on the server, and the plain HTML result is sent back to the browser.
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Wednesday, August 2, 2017

What is PHP file have extension?

  • PHP files have extension ".php"
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What Can PHP Do?

What Can PHP Do?

  • PHP can generate dynamic page content
  • PHP can create, open, read, write, delete, and close files on the server
  • PHP can collect form data
  • PHP can send and receive cookies
  • PHP can add, delete, modify data in your database
  • PHP can be used to control user-access
  • PHP can encrypt data
With PHP you are not limited to output HTML. You can output images, PDF files, and even Flash movies. You can also output any text, such as XHTML and XML.
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How to Set Up PHP on Your Own PC?

Set Up PHP on Your Own PC

 if your server does not support PHP, you must:
  • install a web server
  • install PHP
  • install a database, such as MySQL
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How to Use a Web Host With PHP Support?

Use a Web Host With PHP Support

If your server has activated support for PHP you do not need to do anything.
Just create some .php files, place them in your web directory, and the server will automatically parse them for you.
You do not need to compile anything or install any extra tools.
Because PHP is free, most web hosts offer PHP support.
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Write down the criteria of PHP?

  • PHP runs on various platforms (Windows, Linux, Unix, Mac OS X, etc.)
  • PHP is compatible with almost all servers used today (Apache, IIS, etc.)
  • PHP supports a wide range of databases
  • PHP is free. Download it from the official PHP resource: 
  • PHP is easy to learn and runs efficiently on the server side

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