PHP Unit-II contd..

• Variable scope
• Saving state between Function calls with the static statement
• Arrays Introduction

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Variable scope

• Variable scope is known as its boundary within which it can be visible or accessed from code
• In other words, it is the context within which a variable is defined
• There are only two scopes available in PHP namely local and global scopes.

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Variable scope

• Local variables (local scope)
• Global variables (special global scope)
• Static variables (local scope)
• Function parameters (local scope)

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Variable scope-local scope

• A local scope is a restricted boundary of a variable within which code block it is declared
• That block can be a function, class or any conditional span
• The variable within this limited local scope is known as the local variable of that specific code block

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Variable scope-local scope

<?php

function myfun()

{

$count = 5;

echo $count;

}

myfun();

?>

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Variable scope-global scope

• Variables in global scope can be accessed anywhere from outside a function or class independent of its boundary
• PHP global variables can be defined by using global keyword.
• If we want to use global variables inside a function, we have to prefix the global keyword with the variable. 

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Variable scope-global scope

<?php

$count = 20;

function findcount()

{

global $count;

echo $count;

}

findcount();

echo $count;

?>

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Static variable-local scope

• A static variable is a variable with local scope.
• A static variable does not lose its value when the program execution goes past the scope boundary
• But it can be accessed only within that boundary

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Static variable-local scope

<?php

function counter()

{

static $count = 1;

echo $count;

$count++;

}

counter();

counter();

counter();

?>

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Function parameters-local scope

• Function parameters (arguments) are local variables defined within the local scope of the function on which it is used as the argument.

<?php

  function mynumber($x)

   {

     echo “Number is $x”;

   }

     mynumber(12);

?>

​

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Arrays in PHP

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What is an array?

• An array is a collection of elements of the same data type
• How to create an array in PHP?
• In PHP, the array() function is used to create an array

​

$cars = array(“Maruti”, “BMW”, “volvo”);

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Types of arrays in PHP

• In PHP, there are three types of arrays:
• Indexed arrays - Arrays with a numeric index
• Associative arrays - Arrays with named keys
• Multidimensional arrays - Arrays containing one or more arrays

​

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Indexed arrays in PHP

• An array with a numeric index where values are stored linearly

<?php�$cars = array(“Maruti”, “BMW”, “Toyota”);�echo $cars[0].“,”.$cars[1].“and”. $cars[2];�

?>

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Indexed arrays in PHP

• The index can be assigned manually

​

$cars[0] = “Maruti”;�$cars[1] = "BMW";�$cars[2] = “volvo”;

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Associative Arrays in PHP

• Associative arrays are arrays that use named keys that you assign to them

$age=array(“Ravi”=>"35", “Kiran”=>“37”);�echo “Ravi is”.$age[‘Ravi’]. “years old”;

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Multidimensional arrays in PHP

• A two-dimensional array is an array of arrays

$cars = array�  (�  array("Maruti",21,13),�  array("Volvo",15,13),�  array("BMW",5,2),�  );

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The count() Function�

• The count() function is used to return the length (the number of elements) of an array.

​

<?php�$cars = array("Maruti", "BMW", "Volvo");�echo count($cars);

?>

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Loop Through an Indexed Array�

<?php�$cars=array("Maruti","BMW","Volvo");�$len=count($cars);��for($x = 0; $x < $len; $x++)

{�    echo $cars[$x];�    echo "<br>";�}

?>

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