PHP

PHP

1.Introduction

• PHP is defined as  hypertext preprocessor
• PHP is open source
• This is a server side scripting language.
• PHP can be used to develop dyanamic web pages.
• PHP is executed in the server side.

2. PHP Coding

• Every commands must always ends with semi colon.
• PHP files must be save with .php extension
• PHP coding must be done inside "<?php    ?>"   

   2.1 Hello World

•   Echo keyword is used in PHP to output some message for the user.
• Also we can use HTML elements and attributes during the PHP coding
• Please refer the below code examples.

ex 1: <?php

         echo "Hello World";
     ?>


ex 2: <?php
 
         echo "Hello <br><b>World</b>";
     ?>

   2.2 Commenting in PHP

• There are Three Different ways to Commenting in PHP
  
  1. Single line Comments
  
      //This is a Single Line Comment
  
  2.Multi Line Comments

            /* This 
       is a 
       Multi line
       Comment */

        3. Shell style comment


             #This is a Shell style comment.

  2.3 Variables

• In PHP variables have to be declared with "$" mark.
• PHP is a case sensitive language.
• There are mainly two types of variables which are Global and Local variables. Local variables are restricted to a function or a class.

• There are some variables reserved to PHP

                          ex: Form variables ($_POST,$_GET)
                                Server Variables($_SERVER)   

ex 3: <?php

     $a=10;
     $b=5;

     $ans=$a+$b;

    //only the output will be the answer

  echo $ans;

    //output will be printed with a message

   //concatination symbol in PHP ‘.’ is same as + mark in java or JavaScript

echo ‘The total is’.$ans;
  echo  $ans.’is the total’;
  echo ‘The total is ‘.$ans.’ For your calculation’;

     ?>

 ex 4: <?php
         $value=25;

    //auto recognize variable type as a integer
         
        $name="Vira 360";

    //auto recognize variable type as String

        $value = ($value*8);

        echo "$name ";
        echo $name , $value;

        echo "25 * 8 ",$value;

        echo "25 * 8  =  $value";

   //single quotations will not call the output

        echo '25 * 8 = $value';

    ?>

  ex5: <?php
    echo '<a href='http:/www.google.lk"> Google </a>';
  //html tags can be used in single quotations

      ?>

   2.4 Arithmetic Operation

ex 6: <?php
   
    $number1=1009;
    $number2=2003;

    echo "Add<br>";
    echo $number1+$number2 .'<br>';

    echo "Subtract<br>";
    echo $number1-$number2 .'<br>';

    echo "Product<br>";
    echo $number1*$number2 .'<br>';

    echo "Add<br>";
    echo $number1+$number2 .'<br>';

    echo "Divition<br>";
    echo $number1/$number2 .'<br>';

    ?>

2.5 IF-ELSE

ex 7: <?php
   
    $number1=10;
    $number2=20;

    if($number1==$number2){

    echo "Two number are Equal<br>";
   
    }

    else if($number1<$number2){
   
    echo "Number 2 is greater than Number 1 <br>";
    }

    else{

    echo "Number 2 is Less than Number 1 <br>";
    }

    ?>


2.6 Comparison and Logical Operators


1. $a==$b           -> equals
2. $a===$b         -> equals and same type
3. $a!=$b            -> not equal
4. $a<>$b            -> not equal
5. $a!==$b          -> not identical(not of the same data type)
6. $a<$b              -> less than
7. $a>$b              -> greater than
8. $a<=$b            -> less than or equal
9. $a>=$b            -> greater than or equal


1. $a and $b -> ($a && $b)
2. $a or  $b   -> ($a || $b)


ex 8: <?php
   
    $number1=10;
    $number2=20;
if(($number1==$number2)or($number1==$number2))
    {

    echo "Two number are Equal<br>";
   
    }
     ?>

2.7 Arrays in PHP

ex 9: <?php

    $names=array('Mark','John','Bob');

   //mentioned index will be displayed from the following method
    echo $names[0];
    echo $names[1];
    echo $names[2];   


  //assigning additional value for the array

    $names[3]='july';

  //so it will display as july
    echo $names[3];     
   
   //output the full array

    print_r($names);

 //output will be like this                 //Array([0]=>Mark[1]=>John[2]=>Bob[3]=>July)

    $names[4]='patrik';
    print_r($names);
 
//output will be like this
    //Array([0]=>Mark[1]=>John[2]=>Bob[3]=>July[4]=>Patrik)


   ?>

2.7.2 Associative Arrays

ex 10: <?php

    $names=array('Mark'=>56,'John'=>45,'Bob'=>78);
   
  echo'Weight of Mark is ' .$names['Mark'].'<br>';
   
    print_r($names);

    //output will be like this
    //Array([Mark]=>56[John]=>45[Bob]=>78)

         ?>

2.7.3 Multi Dimensional Array


ex 11: <?php

    /*

    Students
    Name   Age   weight
    Mark    15      46
    John     13      65
    Tom     14      56

    */

    $students=array(array('Mark',15,46),array('John',13,65),array('Tom',14,56));

   //Following wiil be output the array as a Matrix
   

    echo $students[0][0].'<br>';
    echo $students[0][1].'<br>';
    echo $students[0][2].'<br>';
    echo $students[1][0].'<br>';
    echo $students[1][1].'<br>';
    echo $students[1][2].'<br>';
    echo $students[2][0].'<br>';
    echo $students[2][1].'<br>';
    echo $students[2][2].'<br>';

?>
ex 12: <?php

    /*

    Students
    Name Age weight
    Mark 15  46
    John 13  65
    Tom  14  56

    */

    $students=array(array('Name'=>'Mark','Age'=>15,'Weight'=>46),
                                                array('Name'=>'John','Age'=>13,'Weight'=>65),
                                                            array('Name'=>'Tom','Age'=>14,'Weight'=>56));

    echo $students[0]['Name'].'<br>';
    echo $students[0]['Age'].'<br>';
    echo $students[0]['Weight'].'<br>';
    echo $students[1]['Name'].'<br>';
    echo $students[1]['Age'].'<br>';
    echo $students[1]['Weight'].'<br>';
    echo $students[2]['Name'].'<br>';
    echo $students[2]['Age'].'<br>';
    echo $students[2]['Weight'].'<br>';

?>

2.8 While and Do while

• Loop-piece of code that run again and again until the condition is true

ex 13: <?php

$counter=1;
echo "Hello world";

//1-true code will run without stopping
//0-false
//while(1) or while(0)

while($counter<=10){

echo "Hello world <br>"; or echo 'Hello world'.$counter.'<br>';
$counter++

}

• while loop -> until the condition is true code will be executed.

• do while    -> executes at least ones even if condition is true.

2.9 Do While

• execute the code first then check the condition

ex 14: <?php
$counter=1; echo "Hello world";

//1-true code will run without stopping //0-false //while(1) or while(0)

do{
echo "Hello world <br>"; or echo 'Hello world'.$counter.'<br>'; $counter++
}while($counter<=10)

?>

2.10 For Loop

ex 15:

<?php

     

    for(init; condition; increment)
{
    statement(S);
}

?>

ex 16: 

<?php

for($counter=1 ;$counter<=10 ;$counter++)
{
    echo 'Hi'.$counter.'<br>';
}

?>

2.11 PHP Foreach Loop

 
ex 17:

<?php
    $names=array('mark','john','tom','patrik','july')
   
    foreach($names as $name)
    {
      echo $name .'br';
    }
?>

ex 18:

<?php

    /*

    Students
    Name Age weight
    Mark 15  46
    John 13     65
    Tom  14  56

    */

    $students=array(array('Name'=>'Mark',
                  'Age'=>15,
                  'Weight'=>46),
            array('Name'=>'John',
                  'Age'=>13,
                  'Weight'=>65),
            array('Name'=>'Tom',
                  'Age'=>14,
                  'Weight'=>56));


    foreach($students as $student=> $innrerArray)
    {
    echo '<b>'.$student.''</b><br>';
    foreach($innrerArray as $item)
    {
    echo $item.'<br>';
    }

   
?>

2.12 Switch

ex 19: 

<?php
  $number=2;

switch($number)
{
case 1:echo "Number is one";break;
case 2:echo "Number is Two";break;
case 3:echo "Number is Three";break;
default:echo "No entry";
}

?>



2.13 $_GET

• $_GET -> Super user variable which means a variable provided by PHP .
• $_GET['name'] ->square brackets to get values and index we are expecting.
• The value you through the get method will value passed in the address bar

<?php
 echo $_GET["name"]       
?>

• localhost/Get.php?s_name=Mark , The name Mark will be displayed in the address bar.

ex 20: Please try to do the following example 

1.form.html

<html>
<body>
<h1>Student info</h1>

<form action="Get.php" method="get">

<b>Name :<b><input type="text" name="stu_name"><br>
<b>Age :<b><input type="text" name="stu_age"><br>
<b>Weight :<b><input type="text" name="stu_weight"><br>
<input type="submit">
</form>
</body>
</html>



2. GET.php

<?php
 echo 'Name:'.$_GET["stu_name"].'<br>';
 echo 'Name:'.$_GET["stu_age"].'<br>';
 echo 'Name:'.$_GET["stu_weight"].'<br>';       
?>

• so the output will be displayed on the get.php page.Also the results will be displayed on the url.

Using IF for validation

<?php

if(isset($_GET["stu_name"]) && isset($_GET["stu_age"]) && isset($_GET["stu_weight"]))
{

 $name=$_GET["stu_name"];
 $age=$_GET["stu_age"];
 $weight=$_GET["stu_weight"];

if(!empty($name) && !empty($age) && !empty($weight))
{
 echo 'Name:'.$_GET["stu_name"].'<br>';
 echo 'Name:'.$_GET["stu_age"].'<br>';
 echo 'Name:'.$_GET["stu_weight"].'<br>';
}

else{

echo "Please enter all filds";

}

}
       
?>

2.14 $_POST

• Super global variable.
• Url will not be modified just like in GET.
• passed values not will be displayed in url.
• secure than GET.

 ex 21:

  1.form.html

<html>
<body>
<h1>Student info</h1>

<form action="Post.php" method="post">

<b>UserName :<b><input type="text" name="username"><br>

<b>Password :<b><input type="password" name="password"><br>

<input type="submit">
</form>
</body>
</html>

 2. post.php

<?php

$_POST["username"];
$_POST["password"];

if($POST["username"]=="mark" && $POST["password"]=="pass")
{
echo "Password is correct";

}

else
{
echo "password is incorrect";
}

echo 'User Name :'.$_POST["username"].'<br>Password'.$_POST["password"].'<br>';

?>

2.15 Functions

• block of code designed to perform a particular task.
• Used to increase the readability of program,to perform a task in responsive manner.

ex 22:

<?php

function hello()
{
 echo "Hello NSBM<br>";
 echo "Hello NSBM<br>";
 echo "Hello NSBM<br>";       
}


hello();

//Calling the function
?>


2.15.2 With Arguments

ex 23:

 <?php

function add($num1,$num2)
{
 echo $num1 + $num2 .'<br>';   
}


add(899,1000);

add(99,1000);

add(899,100);


?>


2.15.3 Return value


ex 24: 

<?php

function add($num1,$num2)
{
 $result=$num1 + $num2 ;

    return $result;
   
}

$add1=add(899,1000);
echo add(899,1000).'<br>';

$add2=add(2000,1100);
echo add(2000,1100).'<br>';

echo $add1 * $add2;

?>


2.15.4 Date and Time Functions

ex 25:

<?php

$date1=date('d/m/Y');
$date2=date('d.m.Y');
$date3=date('d-m-Y');

//D shows the days name

echo $date1;
echo $date2;
echo $date3;

$time=date('H-i-s');
echo $time;

?>


2.15.4 Global Variables and Functions
ex 26:

<?php

$name="Mark";

echo $name;

function showName()
{
    global $name;
    echo 'The name is '.$name;
}

showname();
?>

2.16 include() & require()

ex 27:

1.header.php

<html>
<body>
<h1>Programming</h1>
</body>
</html>
<?php
$name = 'Devin';
?>

2.page1.php

<?php

include 'header.php';

$page1 ='we are in page 1';
echo $page1;

echo $name;
?>

3.page2.php

<?php

include 'header.php';

$page2 ='we are in page 2';
echo $page2;

echo $name;
?>

• require is same as include
• require keyword responsible if it cannot find mentioned file or php file it will kill your current page.
• You can also include_once('header.php') or require_once().

ex 28:

<?php

include 'header.php';
include 'header.php';
include_once('header.php');

//so when we have used this included page will executes once

$page1 ='we are in page 1';
echo $page1;

?>

• same thing happens to require_once

To be Continued...