Chapter - 3

Arrays

PHP: Hypertext Preprocessor

Outlineo What is an array ?o Indexed arrayo Associative arrayo Multidimensional array 

What is an Array? An array is a special variable, which can

store multiple values in one single variable.

An array can hold many values under a

single name, and you can access the

values by referring to an index number.

What is an array? 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?

The best solution here is to use an array!

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.

What is an array?

In PHP, the array() function is used to

create an array: array();

Kind of arrays in PHP Indexed  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

Indexed Arrays A numeric array stores each array element

with a numeric index.

There are two ways to create indexed

arrays:

Indexed Arrays1. In the following example the index are automatically

assigned (the index starts at 0):

- $cars = array ("Saab","Volvo","BMW","Toyota");

2. The following example we assign the index manually:]

1. $cars[0]="Saab";

2. $cars[1]="Volvo";

3. $cars[2]="BMW";

4. $cars[3]="Toyota";

$array_name = array(val1, val2, val3,val4,……);

Indexed Arrays - Example<?php

$cars[0]="Saab";$cars[1]="Volvo";$cars[2]="BMW";$cars[3]="Toyota"; echo $cars[0] . " and " . $cars[1] . " are Swedish cars.";

?>

Indexed Arrays - Example<?php

$array = array(1, 2,3,4,5,6,7,8,9);for ($i = 0; $i < 9; $i++)

  {     echo “Number : “. $array[$i];

}?>

Print_r() Function

Print construction of array as group of

locations and the value stored in it print_r ($expression [, bool $return = false ] )

Print_r()

<?php$arr = array(1,2,3,4,5);Print_r($arr);

?>Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )

Count() Function

This is build in function ,counts all

elements in an array, or something in an

object.int count ($var [, int $mode = COUNT_NORMAL ] )

Count Function - Example<?php

$a[0] = 1;$a[1] = 3;$a[2] = 5;$result = count($a); // $result == 3$b[0]  = 7;$b[5]  = 9;$b[10] = 11;$result = count($b); // $result == 3$result = count(null);// $result == 0$result = count(false);// $result == 1?>

Count Function - Example<?php

$array = array(“M”, ”u”,”n”,”e”,”e”,”r”);for ($i = 0; $i < count($array); $i++)

  {     echo  $array[$i];

}?>

Foreach

For every loop iteration, the value of the current array

element is assigned to $value (and the array pointer is

moved by one) - so on the next loop iteration, you'll be

looking at the next array value.

foreach ($array as $value)  {  code to be executed;  }

Foreach - Example

<?php$x=array("one","two","three");foreach ($x as $value)  {  echo $value . "<br />";  }

?>

Foreach - Example<?php

$colors = array('red', 'blue', 'green', 'yellow');foreach ($colors as $color) {    echo "Do you like $color?\n";

}

?>

in_array() Function

The in_array() function searches an array for a specific value. This function returns TRUE if the value is found in the array, or

FALSE otherwise.

in_array(search,array,type)

Parameter Description

search Required. Specifies the what to search for

array Required. Specifies the array to search

type Optional. If this parameter is set, the in_array() function searches for the search-string and specific type in the array

Note: If the search parameter is a string and the type parameter is set to TRUE, the search is case-sensitive.

in_array() Function - Example<?php

$os = array("Mac", “W7", “W8", "Linux");if (in_array(“XP", $os)) {    echo "Got XP";}if (in_array(“Mac", $os)) {    echo "Got Mac";}

?>

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.

Associative Arrays

• $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34);

or• $ages['Peter'] = "32";

$ages['Quagmire'] = "30";$ages['Joe'] = "34";

$array_name= array($index1=>$val1, $index1=>$val1,…..);

Associative Arrays

<?php

$arr = array("foo" => "bar", 12 => true);

echo $arr["foo"]; // bar

echo $arr[12];    // 1

?>

Associative Arrays - example

<?php// This array is the same as ...array(5 => 43, 32, 56, "b" => 12);// ...this arrayarray(5 => 43, 6 => 32, 7 => 56, "b" => 12);?>

Associative Arrays - example<?php

$ages['Peter'] = "32";$ages['Quagmire'] = "30";$ages['Joe'] = "34";

echo "Peter is " . $ages['Peter'] . " years old.";?>

Associative Arrays - example<?php

$arr = array(5 => 1, 12 => 2);

$arr[] = 56;    // This is the same as $arr[13] = 56;

                // at this point of the script

$arr["x"] = 42; // This adds a new element to

                // the array with key "x"

unset($arr[5]); // This removes the element from the array

unset($arr);    // This deletes the whole array

?>

Associative Arrays - example

<?php

$arr = array("somearray" => array(6 => 5, 13 => 9, "a" =

> 42));

echo $arr["somearray"][6];    // 5

echo $arr["somearray"][13];   // 9

echo $arr["somearray"]["a"];  // 42

?>

Multidimensional 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,

$myArray = array( array( value1, value2, value3 ), array( value4, value5,

value6 ), array( value7, value8, value9 ) );

Multidimensional Arrays<?php

$fruits = array ( "fruits"  => array ( "a" => "orange",

"b" => "banana“,"c" => "apple”),"numbers" => array ( 1,

2,3,4,5,6), "holes"   => array ("first“,5 => "second“,"third

”));

echo $fruits["holes"][5];    // prints "second"

echo $fruits["fruits"]["a"]; // prints "orange"

?>

Multidimensional Arrays<?php

$families = array(“capital"=>array(“A“,“B“,“C”),  “small"=>array(“a”, “b”, “c”),

“number"=>array(“1“,“2“,”3”));foreach($families as $value){foreach($value as $values){echo $values.” ”;}Echo “<br/>”}

?>

Multidimensional Arrays<?php

$try[] = array("11", "12", "15", "22", "41", "42"); $try[] = array("6", "7", "16", "17", "22", "23"); $count = count ($try); for ($i=0; $i<$count; $i++){ $countmore=count($try[0]); for ($j=0; $j < $countmore; $j++){ print ("i$i j$j " . $try[$i][$j] . "<br> "); } print ("<br>"); }

?>

Multidimensional Arrays<?php

$try[] = array("11", "12", "15", "22", "41", "42");

$try[] = array("6", "7", "16", "17", "22", "23"); $count = count ($try); for ($i=0;

$i<$count; $i++)

{

$countmore=count($try[0]);

for ($j=0; $j < $countmore; $j++)

{ print ("i$i j$j " . $try[$i][$j] . "<br> "); }

print ("<br>");

}

?>