Arrays Introduction What is an Array An array

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Arrays

Arrays

Introduction

Introduction

What is an Array? An array stores multiple values in one single variable.

What is an Array? An array stores multiple values in one single variable.

What is an Array? A variable is a storage area holding a number or

What is an Array? A variable is a storage area holding a number or text. The problem is, a variable will hold only one value. An array is a special variable, which can store multiple values in one single variable. If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this: $cars 1="Saab"; $cars 2="Volvo"; $cars 3="BMW“ However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300?

Arrays An array can hold all your variable values under a single name. And

Arrays An array can hold all your variable values under a single name. And you can access the values by referring to the array name. Each element in the array has its own index so that it can be easily accessed. In PHP, there are three kind of arrays: Numeric array - An array with a numeric index Associative array - An array where each ID key is associated with a value Multidimensional array - An array containing one or more arrays

Types of Arrays

Types of Arrays

Numeric Arrays A numeric array stores each array element with a numeric index. There

Numeric Arrays A numeric array stores each array element with a numeric index. There are two methods to create a numeric array. 1. In the following example the index are automatically <? php assigned (the index starts at 0) $cars=array("Saab", "Volvo", "BMW", "Toyota"); ? > 2. In the following example we assign the index manually: <? php $cars[0]="Saab"; $cars[1]="Volvo"; $cars[2]="BMW"; $cars[3]="Toyota"; ? >

In the following example you access the variable values by referring to the

In the following example you access the variable values by referring to the array name and index: <? php $cars[0]="Saab"; $cars[1]="Volvo"; $cars[2]="BMW"; $cars[3]="Toyota"; echo $cars[0]. " and ". $cars[1]. " are Swedish cars. "; ? > The code above will output: Saab and Volvo are Swedish cars.

Associative Arrays An associative array, each ID key is associated with a value. When

Associative Arrays An associative array, each ID key is associated with a value. When storing data about specific named values, a numerical array is not always the best way to do it. With associative arrays we can use the values as keys and assign values to them. Example 1 In this example we use an array to assign ages to the different persons: <? php $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34); ? >

This example is the same as example 1, but shows a different way

This example is the same as example 1, but shows a different way of creating the array: <? php $ages['Peter'] = "32"; $ages['Quagmire'] = "30"; $ages['Joe'] = "34"; ? > The ID keys can be used in a script: <? php $ages['Peter'] = "32"; $ages['Quagmire'] = "30"; $ages['Joe'] = "34"; echo "Peter is ". $ages['Peter']. " years old. "; ? > The code above will output: Peter is 32 years old.

Multi-dimentional Arrays In a multidimensional array, each element in the main array can also

Multi-dimentional Arrays In a multidimensional array, each element in the main array can also be an array. And each element in the sub -array can be an array, and so on. Example 1 In this example we create a multidimensional array, with automatically assigned ID keys: : <? php $families = array("Griffin"=>array("Peter", "Lois ", "Megan” ), "Quagmire"=>array("Glenn” ), "Brown"=>array("Cleveland“, "Loretta“, "Junior” ) ); ? >

The array above would look like this if written to the <? php

The array above would look like this if written to the <? php output: Array ( [Griffin] => Array ( [0] => Peter [1] => Lois [2] => Megan ) [Quagmire] => Array ( [0] => Glenn ) [Brown] => Array ( [0] => Cleveland [1] => Loretta [2] => Junior ) )? >

Example 1 Lets try displaying a single value from the array above: <? php

Example 1 Lets try displaying a single value from the array above: <? php $families = array("Griffin"=>array("Peter", "Lois ", "Megan” ), "Quagmire"=>array("Glenn” ), "Brown"=>array("Cleveland“, "Loretta“, "Junior” ) ); echo "Is ". $families['Griffin'][2]. " a part of the Griffin family? " ? > The code above will output: Is Megan a part of the Griffin family?

Manipulating Arrays

Manipulating Arrays

Fetching Data For Loop method Foreach() method Array_keys() Array_values() List() Extract()

Fetching Data For Loop method Foreach() method Array_keys() Array_values() List() Extract()

For Loop Method You can fetch the data from an array using FOR statements.

For Loop Method You can fetch the data from an array using FOR statements. sizeof($array_name) – it returns the size (number of elements within) the array. <html> <body> Xavier University Colleges <ul> <? php $colleges = array( "Arts and Sciences", "Engineering", "Agriculture", "Nursing", "CIT", "SBM", "Education"); $total_list=sizeof($colleges); for($i=0; $i<$total_list; $i++) { echo "<li> $colleges[$i]"; } ? > </ul> </body> </html>

Foreach() Method This loop runs once for each element of the array, moving forward

Foreach() Method This loop runs once for each element of the array, moving forward through the array on each iteration. On each run, the statements within the curly braces are executed, and the currently selected array element is made available through a temporary loop variable. <html> <body> Xavier University Colleges <ul> <? php $colleges = array( "Arts and Sciences", "Engineering", "Agriculture", "Nursing", "CIT", "SBM", "Education"); foreach($colleges as $item) { echo "<li> $item"; }? > </ul> </body> </html>

Keys and Values $menu = array(‘breakfast’ => ‘bacon and eggs’, ‘lunch’ => ‘chicken’, ‘dinner’

Keys and Values $menu = array(‘breakfast’ => ‘bacon and eggs’, ‘lunch’ => ‘chicken’, ‘dinner’ => ‘fish’); Array name = menu Iteration Keys Value 0 Breakfast Bacon and eggs 1 Lunch Chicken 2 Dinner fish

Array _keys() Use this to returns keys from an array <? php $menu =

Array _keys() Use this to returns keys from an array <? php $menu = array('breakfast' => 'bacon and eggs', 'lunch' => 'chicken', 'dinner' => 'fish'); $result = array_keys($menu); foreach ($result as $food) { echo "$food "; } ? >

Array _values() Use this to returns values from an array. <? php $menu =

Array _values() Use this to returns values from an array. <? php $menu = array('breakfast' => 'bacon and eggs', 'lunch' => 'chicken', 'dinner' => 'fish'); $result = array_values($menu); foreach ($result as $food) { echo "$food "; } ? >

list() Use this to convert array of values to individual variables <? php $menu

list() Use this to convert array of values to individual variables <? php $menu = array('breakfast' , 'lunch' , 'dinner'); list($food 1, $food 2, $food 3) = $menu; echo "$food 1 "; echo "$food 2 "; echo "$food 3 "; ? >

extract() Use this to convert array of value pairs to individual <? php variables

extract() Use this to convert array of value pairs to individual <? php variables $menu = array('breakfast' => 'bacon and eggs', 'lunch' => 'chicken', 'dinner' => 'fish'); extract ($menu); echo "$breakfast "; echo "$lunch "; echo "$dinner "; ? >

Fetching Data Array_shift() Array_pop() Array_push() Array_unshift()

Fetching Data Array_shift() Array_pop() Array_push() Array_unshift()

Keys and Values $students = array(‘Tom’, ’Jill’, ’Harry’); Array name = students Iteration Keys

Keys and Values $students = array(‘Tom’, ’Jill’, ’Harry’); Array name = students Iteration Keys 0 Tom 1 Jill 2 Harry

Array manipulation Function Command Example Remove an element from the BEGINNING Array_shift() Array_shift($students); Add

Array manipulation Function Command Example Remove an element from the BEGINNING Array_shift() Array_shift($students); Add and element to the BEGINNING Array_unshift( ) array_unshift($students, ‘John’); Remove an element from the END Array_pop() Array_pop($students); Add and element to the END Array_push() Array_push($students, ‘James’); Show array results Print_r() Print_r($students)

Application of print_r() <? php $students = array('Tom', 'Jill', 'Harry'); print_r($students); echo " ";

Application of print_r() <? php $students = array('Tom', 'Jill', 'Harry'); print_r($students); echo " "; foreach($students as $items) { print_r($items); echo " "; } ? >

$students = array(‘A’, ’D’, ’E’); p

$students = array(‘A’, ’D’, ’E’); p

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