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Introduction to PHP
Lecture 10

Table of
Content
1.What is PHP Arrays
2.Types of Arrays in PHP
3. DifferentTypes of Loops in PHP
4. PHP Functions
5. GET Method
6. POST Method

1.Whatis
PHPArrays
Arrays are complex variables that allow us to
store more than one value or a group of values
under a single variable name. Let's suppose you
want to store colors in your PHP script. Storing
the colors one by one in a variable could look
something like this:
<?php
$color1 = "Red";
$color2 = "Green";
$color3 = "Blue";
?>

There are three types of arrays that you can
create. These are:
 Indexed array — An array with a numeric key.
 Associative array — An array where each key
has its own specific value.
 Multidimensional array — An array
containing one or more arrays within itself.
2.Typesof
Arraysin
PHP

<!DOCTYPE html>
<html lang="en">
<head>
<title>PHP Indexed Arrays</title>
</head>
<body>
<?php
$colors = array("Red", "Green",
"Blue");
// Printing array structure
print_r($colors);
?>
</body>
</html>
Output:
Array ( [0] => Red [1] => Green [2] => Blue)
Example
onIndexed
Array

<!DOCTYPE html>
<html lang="en">
<head>
<title>PHP Indexed Arrays</title>
</head>
<body>
<?php
$colors[0] = "Red";
$colors[1] = "Green";
$colors[2] = "Blue";
print_r($colors);
?>
</body>
</html>>
Thisis
equivalenttothe
following
example,in
whichindexes
areassigned
manually:

 In an associative array, the keys assigned to values
can be arbitrary and user defined strings. In the
following example the array uses keys instead of
index numbers:
Associative
Arrays

<!DOCTYPE html>
<html lang="en">
<head>
<title>PHP Associative Array</title>
</head>
<body>
<?php
$ages = array("Peter"=>22, "Clark"=>32, "John"=>28);
print_r($ages);
?>
</body>
</html>
Output:
Array ( [Peter] => 22 [Clark] => 32 [John] => 28 )
Exampleon
Associative
Array

 The multidimensional array is an array in which each element
can also be an array and each element in the sub-array can be an
array or further contain array within itself and so on. An
example of a multidimensional array will look something like
this:
Multidimensional
Arrays

<body>
<?php
// Define nested array
$contacts = array(
array(
"name" => "Peter Parker",
"email" => "peterparker@mail.com",
),
array(
"name" => "Clark Kent",
"email" => "clarkkent@mail.com",
),
array(
"name" => "Harry Potter",
"email" => "harrypotter@mail.com",
)
);
// Access nested value
echo "Peter Parker's Email-id is: " . $contacts[0]["email"];
?>
Output:
Peter Parker's Email-id is: peterparker@mail.com
Exampleon
Multidimensional
Array

Loops are used to execute the same block of code again and again, as long as a
certain condition is met. The basic idea behind a loop is to automate the
repetitive tasks within a program to save the time and effort. PHP supports
four different types of loops.
 while — loops through a block of code as long as the condition specified
evaluates to true.
 do…while — the block of code executed once and then condition is
evaluated. If the condition is true the statement is repeated as long as the
specified condition is true.
 for — loops through a block of code until the counter reaches a specified
number.
 foreach — loops through a block of code for each element in an array.
 You will also learn how to loop through the values of array
using foreach() loop at the end of this chapter. The foreach() loop work
specifically with arrays.

DifferentTypes
ofLoopsin
PHP

The while statement will loops through a block of code as long as the
condition specified in the while statement evaluate to true.
while(condition){
// Code to be executed
}
Internt applications-Lecture 11
PHPwhile
Loop

The example below define a loop that starts with $i=1. The loop will continue to
run as long as $i is less than or equal to 3. The $i will increase by 1 each time the
loop runs:
<!DOCTYPE html>
<html lang="en">
<head>
<title>PHP while Loop</title>
</head>
<body>
<?php
$i = 1;
while($i <= 3){
$i++;
echo "The number is " . $i . " ";
}
?>
</body>
</html>
Output:
The number is 2
The number is 3
The number is 4
PHPwhileLoop
Example

The do-while loop is a variant of while loop, which evaluates the condition at
the end of each loop iteration. With a do-while loop the block of code
executed once, and then the condition is evaluated, if the condition is true,
the statement is repeated as long as the specified condition evaluated to is
true.
do{
}
while(condition);
PHPdo…while
Loop

<!DOCTYPE html>
<html lang="en">
<head>
<title>PHP do-while Loop</title>
</head>
<body>
<?php
$i = 1;
do{
$i++;
}
while($i <= 3);
?>
</body>
</html>
PHPdo-while
Loop
Example
Output:
The number is 2
The number is 3
The number is 4

The for loop repeats a block of code as long as a certain condition is met. It is
typically used to execute a block of code for certain number of times.
for(initialization; condition; increment){
}
The parameters of for loop have following meanings:
 initialization — it is used to initialize the counter variables, and evaluated
once unconditionally before the first execution of the body of the loop.
 condition — in the beginning of each iteration, condition is evaluated. If it
evaluates to true, the loop continues and the nested statements are executed.
If it evaluates to false, the execution of the loop ends.
 increment — it updates the loop counter with a new value. It is evaluate at the
end of each iteration.
PHPforLoop

<!DOCTYPE html>
<html lang="en">
<head>
<title>PHP for Loop</title>
</head>
<body>
<?php
for($i=1; $i<=3; $i++){
}
?>
</body>
</html>
Output:
The number is 2
The number is 3
The number is 4
PHPForLoop
Example

The foreach loop is used to iterate over arrays.
foreach($array as $value){
}
PHPforeach
Loop

<!DOCTYPE html>
<html lang="en">
<head>
<title>PHP foreach Loop</title>
</head>
<body>
<?php
$colors = array("Red", "Green", "Blue");
// Loop through count array
foreach($colors as $value){
echo $value . " ";
}
?>
</body>
</html>
Output:
Red
Green
Blue
PHPforeachLoop
Example

<?php
$superhero = array(
"name" => "Peter Parker",
"email" => "peterparker@mail.com",
"age" => 18
);
// Loop through superhero array
foreach($superhero as $key => $value){
echo $key . " : " . $value . " ";
}
?>
</body>
</html>
Output:
name : Peter Parker
email : peterparker@mail.com
age : 18
PHPforeachLoop
Example

 A function is a self-contained block of code that performs a specific
task.
 PHP has a huge collection of internal or built-in functions that you
can call directly within your PHP scripts to perform a specific task,
like gettype(), print_r(), var_dump, etc.
Internt applications-Lecture 11
PHPFunctions
1.PHPBuilt-in
Functions

In addition to the built-in functions, PHP also allows you to define your own
functions. It is a way to create reusable code packages that perform specific
tasks and can be kept and maintained separately form main program. Here
are some advantages of using functions:
 Functions reduces the repetition of code within a program — Function
allows you to extract commonly used block of code into a single component.
Now you can perform the same task by calling this function wherever you
want within your script without having to copy and paste the same block of
code again and again.
 Functions makes the code much easier to maintain — Since a function
created once can be used many times, so any changes made inside a
function automatically implemented at all the places without touching the
several files.
 Functions makes it easier to eliminate the errors —When the program is
subdivided into functions, if any error occur you know exactly what function
causing the error and where to find it.Therefore, fixing errors becomes
much easier.
 Functions can be reused in other application — Because a function is
separated from the rest of the script, it's easy to reuse the same function in
other applications just by including the php file containing those functions.
2.PHPUser-
Defined
Functions

The basic syntax of creating a custom function can be give with:
function functionName(){
}
The declaration of a user-defined function start with the
word function, followed by the name of the function you want to
create followed by parentheses i.e. () and finally place your
function's code between curly brackets {}.
Creatingand
Invoking
Functions

You can specify parameters when you define your function to accept input
values at run time. The parameters work like placeholder variables within a
function; they're replaced at run time by the values (known as argument)
provided to the function at the time of invocation.
function myFunc($oneParameter, $anotherParameter){
}
You can define as many parameters as you like. However for each parameter
you specify, a corresponding argument needs to be passed to the function
when it is called.
Functionswith
Parameters

<?php
// Defining function
function getSum($num1, $num2){
$sum = $num1 + $num2;
echo "Sum of the two numbers $num1 and $num2 is : $sum";
}
// Calling function
getSum(10, 20);
?>
</body>
</html>
Output:
Sum of the two numbers 10 and 20 is : 30
Functionswith
Parameters

<?php
// Defining function
function divideNumbers($dividend, $divisor){
$quotient = $dividend / $divisor;
$array = array($dividend, $divisor, $quotient);
return $array;
}
// Assign variables as if they were an array
list($dividend, $divisor, $quotient) = divideNumbers(10, 2);
echo $dividend . " "; // Outputs: 10
echo $divisor . " "; // Outputs: 2
echo $quotient . " "; // Outputs: 5
?>
</body>
</html>
Output:
10
2
5
Functionswith
Parameters

<?php
/* Defining a function that multiply a number
by itself and return the new value */
function selfMultiply(&$number){
$number *= $number;
return $number;
}
$mynum = 5;
echo $mynum . " "; // Outputs: 5
selfMultiply($mynum);
echo $mynum . " "; // Outputs: 25
?>
</body>
</html>
Output:
5
25
Functionswith
Parameters

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