The document discusses arrays in PHP, including the three types of arrays (indexed, associative, and multidimensional), how to create and access array elements, functions for manipulating arrays like sort(), merge(), search(), and more. Key array functions covered are sort(), asort(), ksort(), array_merge(), array_intersect(), array_diff(), and the list() function for assigning array values to variables.

1. ARRAYS IN PHP

2. array();
three types of arrays:
• Indexed arrays - Arrays with numeric index
• Associative arrays - Arrays with named keys
• Multidimensional arrays - Arrays containing one
or more arrays

3. PHP Indexed Arrays
• two ways to create indexed arrays:
$cars=array("Volvo","BMW","Toyota");
Or :
• $cars[0]="Volvo";
$cars[1]="BMW";
$cars[2]="Toyota";

4. EXAMPLE
<?php
$cars=array("Volvo","BMW","Toyota");
echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] .
".";
?>

5. Get The Length of an Array - The count() Function
used to return the length of an array:
<?php
$cars=array("Volvo","BMW","Toyota");
echo count($cars);
?>

6. Loop Through an Indexed Array
<?php
$cars=array("Volvo","BMW","Toyota");
$arrlength=count($cars);
for($x=0;$x<$arrlength;$x++)
{
echo $cars[$x];
echo "<br>";
}
?>

7. PHP Associative Arrays
• Associative arrays are arrays that use named keys that you
assign to them.
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
or:
$age['Peter']="35";
$age['Ben']="37";
$age['Joe']="43";
• The named keys can then be used in a script:
Example
<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
echo "Peter is " . $age['Peter'] . " years old.";
?>
•

8. Loop Through an Associative
Array
• use a foreach loop
Example
• <?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
?>

9. Multidimensional Arrays
• An array can also contain another array as a value, which in
turn can hold other arrays as well.
Example
<?php
// A two-dimensional array:
$cars = array
(
array("Volvo",100,96),
array("BMW",60,59),
array("Toyota",110,100)
);
?>

10. $families = array
(
"Griffin"=>array
(
"Peter",
"Lois",
"Megan"
),
"Quagmire"=>array
(
"Glenn"
),
"Brown"=>array
(
"Cleveland",
"Loretta",
"Junior"
)
);

11. Array
(
[Griffin] => Array
(
[0] => Peter
[1] => Lois
[2] => Megan
)
[Quagmire] => Array
(
[0] => Glenn
)
[Brown] => Array
(
[0] => Cleveland
[1] => Loretta
[2] => Junior
)
)

12. echo "Is " . $families['Griffin'][2] .
" a part of the Griffin family?";
• Output
• Is Megan a part of the Griffin family?

13. Array functions

15. explode()
• Has 2 arguments the separator and source string
and returns an array.
echo $arr;
?>

16. implode()
• to reverse the process, joining the elements of an array into a
single string using user-supplied “glue.”
<?php
// define array
$arr = array('one', 'two', 'three', 'four');
// convert array to string
// output: 'one and two and three and four'
$str = implode(' and ', $arr);
echo $str;
?>

17. range()
• This function accepts two end points and returns an
array containing all the numbers between those end
points.
<?php
// define array
$arr = range(1,1000);
echo $arr;
?>

18. min() and max()
They accept an array of numbers and return the
smallest and largest values in the array respectively.
<?php
$arr = array(7, 36, 5, 48, 28, 90, 91, 3, 67, 42);
echo 'Minimum is ' . min($arr) . ' and maximum is ' .
max($arr);
?>

19. array_slice()
array_slice() function, which accepts three arguments: the original
array, the index position (offset) at which to start slicing, and
the number of elements to return from the starting offset.
<?php
$rainbow = array('violet', 'indigo', 'blue', 'green', 'yellow‘,'orange', 'red');
// output: ('blue', 'green', 'yellow')
$arr = array_slice($rainbow, 2, 3);
echo $arr;
?>
• To extract a segment from the end of an array (rather than the
beginning), pass array_slice() a negative offset
• $arr = array_slice($rainbow, -5, 3);

20. Adding and Removing Array Elements
• array_unshift() function adds an element to the
beginning of an array;
• array_shift() function removes the first element of
an array;
• array_push() function adds an element to the end of
an array;
• array_pop() function removes the last element of
an array.

21. <?php
$movies = array('The Lion King', 'Cars', 'A Bug's Life');
// remove element from beginning of array
array_shift($movies);
// remove element from end of array
array_pop($movies);
// add element to end of array
array_push($movies, 'Ratatouille');
// add element to beginning of array
array_unshift($movies, 'The Incredibles');
// print array
// output: ('The Incredibles', 'Cars', 'Ratatouille')
echo $movies;
?>

22. Removing Duplicate Array Elements
• array_unique() function, which accepts an array and
returns a new array containing only unique values.
<?php
$duplicates = array('a', 'b', 'a', 'c', 'e', 'd', 'e');
// output: ('a', 'b', 'c', 'e', 'd')
$uniques = array_unique($duplicates);
echo $uniques;
?>

23. Randomizing and Reversing
Arrays
• shuffle() function re-arranges the elements of an array
in random order,
• array_reverse() function reverses the order of an array’s
elements.
<?php
$rainbow = array('violet', 'indigo', 'blue', 'green', 'yellow‘,'orange', 'red');
// randomize array
shuffle($rainbow);
echo $rainbow;
// output: ('red', 'orange', 'yellow', 'green', 'blue‘, 'indigo', 'violet')
$arr = array_reverse($rainbow);
echo $arr;
?>

24. Searching Arrays
• in_array() function looks through an array for a
specified value and returns true if found.
<?php
// define array
$cities = array('London', 'Paris', 'Barcelona', 'Lisbon', 'Zurich');
// search array for value
echo in_array('Barcelona', $cities);
?>

25. • the array_key_exists() function looks for a match to
the specified search term among an array’s key
<?php
$cities = array("United Kingdom" => "London",
"United States" => "Washington",
"France" => "Paris“,"India" => "Delhi”);
// search array for key
echo array_key_exists('India', $cities);
?>

26. Sorting an array
• sort() function, which lets you sort numerically
indexed arrays alphabetically or numerically, from
lowest to highest value.
<?php
$data = array(15,81,14,74,2);
// output: (2,14,15,74,81)
sort($data);
echo $data;
?>

27. • asort() function, which maintains the correlation
between keys and values while sorting.
<?php
$profile = array("fname" => "Susan“,"lname" =>
"Doe“,"sex" => "female“,"sector" => "Asset
Management“ );
// output: ('sector' => 'Asset Management‘, 'lname' => 'Doe‘, 'fname' => 'Susan‘, 'sex' =>
'female')
asort($profile);
echo $profile;
?>

28. • ksort() function, which uses keys instead of
values when performing the sorting.
$profile = array("fname" => "Susan“,"lname" => "Doe",
"sex" => "female“,"sector" => "Asset Management”);
// output: ('fname' => 'Susan‘, 'lname' => 'Doe‘,'sector' => 'Asset Management‘, 'sex' =>
'female')
ksort($profile);
echo $profile;
?>
• To reverse the sorted sequence generated by sort(), asort(),
and ksort(), use the rsort(), arsort(), and krsort() functions
respectively.

29. Merging Arrays
• merge one array into another with its array_merge()
function, which accepts one or more array variables
<?php
$dark = array('black', 'brown', 'blue');
$light = array('white', 'silver', 'yellow');
// output: ('black', 'brown', 'blue‘, 'white', 'silver', 'yellow')
$colors = array_merge($dark, $light);
echo $colors;
?>

30. Comparing Arrays
• the array_intersect() function returns the values
common to two arrays
• array_diff() function returns the values from the first
array that don’t exist in the second.
<?php
$orange = array('red', 'yellow');
$green = array('yellow', 'blue');
// output: ('yellow')
$common = array_intersect($orange, $green);
echo $common;
// find elements in first array but not in second
// output: ('red')
$unique = array_diff($orange, $green);
echo $unique;
?>

31. PHP list() Function
• The list() function is used to assign values to a list of
variables in one operation.
• Syntax
list(var1, var2, ...)
• Example :
• <?php
$my_array = array("Dog","Cat","Horse");
list($a, , $c) = $my_array;
echo "Here I only use the $a and $c variables.";
?>