Lecture 5 array in PHP.pptxLecture 10 CSS part 2.pptxvvvvvvvvvvvvvv

Chapter 19-2
PHP
LECTUR 5:
ARRAYS IN
PHP
CHAPTER 19
Web-Based Design
IT210
1

OBJECTIVES
By the end of this lecture student will be able to:
 Understanding array concept.
 Creating arrays
 Understanding the difference types of array
 Dealing with arrays by printing ,adding , deleting ,changing
elements from array
2

OUTL
INE
3
Arrays in PHP.
Types of Array.
Initializing and
Manipulating Arrays.

ARRAYS IN PHP
 An array is a group of data type which is used to store multiple values in a
single variable.
 Array names: like other variables, begin with the $ symbol.
 Individual array elements are accessed by following the array’s variable
name with an index enclosed in square brackets ([]).
 Array index: The location of an element in an array is known as its index.
The elements in an ordered array are arranged in ascending numerical
order starting with zero—the index of the first array element is 0, the index
of the second is 1, and so on.
4

ARRAYS IN PHP
From the picture:
 What is the array
name?
 How many element
does it contain ?
 What is the index of
"Fish" element ?
5
$my_array= [7, "24" , "Fish", "hat stand"]

ARRAY TYPES
 There are three types of arrays in PHP, which are as follows:
6
•It use integer/numbers as their index number to identify each item of the array.
• Array element index start with 0, the next is 1, and so on.
1.Numeric Index Array (ordered array):
• Array inside another array
Nested Array:
• Arrays with nonnumeric index
Associative Array:

CREATING ARRAYS IN PHP
There are two ways to create an array in PHP:
1. Creating Arrays with array() function
e.g: $my_array = array(0, 1, 2);
2. Creating Arrays with Short Syntax
e.g: $my_array = [0, 1, 2];
7

CREATING ARRAYS WITH array()
FUNCTION
 Constructing ordered arrays with a built-in PHP function: array().
 The array() function returns an array.
 Each of the arguments with which the function was invoked becomes
an element in the array (in the order they were passed in).
8
$my_array = array(0, 1, 2);
$string_array = array("first element", "second element");
$mixed_array = array(1, "chicken", 78.2, "bubbles are
crazy!");
To read more about built-in PHP function: array().

CREATING ARRAYS WITH SHORT
SYNTAX
 Creating an array is also possible by wrapping comma-separated
elements in square brackets ([ ]).
9
$my_array = [0, 1, 2];
$string_array = ["first element", " second element "];
$mixed_array = [1, "chicken", 78.2, "bubbles are crazy! "];

count() FUNCTION
 Function count returns the total number of elements in the array.
10
$my_array = [0, 1, 2];
$string_array = ["first element", " second element "];
$mixed_array = [1, "chicken", 78.2, "bubbles are crazy! "];
echo count($my_array);
echo count($string_array);
echo count($mixed_array);
To read more built-in PHP count() function
output 3
output 2
output 4

PRINTING ARRAYS WITH print_r()
FUNCTION
 Since arrays are a more complicated data type than strings or integers,
using echo won’t have the desired result:
11
$my_array = [0, 1, 2];
echo $my_array;
print_r() function: is PHP built-in functions that print the contents of the
array
$my_array = [0, 1, 2];
print_r($my_array);
Echo “ ”;
This will output the
array in the following
format:
Array
(
[0 ]=> 0
[1] => 1
[2] => 2
)
To read more about built-in print_r() function
array:
array

PRINTING ARRAYS WITH implode()
FUNCTION
 implode() function: is PHP built-in functions that print the element in
the array list by converting the array into a string.
 implode() function takes two arguments: a string to use between each
element (the $glue), and the array to be joined together (the $pieces):
12
$my_array = [0, 1, 2];
echo implode(", " , $my_array);
array in the following
format:
0, 1 , 2
To read more about built-in implode() function.

PRINTING THE ARRAY
ELEMENTS USING for LOOP
It possible to print the elements of array using for loop
Hint:
 always start the counter with 0 (why?)
 Always increase the loop by 1 (why?)
 Use count() function in the condition to identify the exact length of the array
13
$my_array = [0, 1, 2];
for( $i = 0; $i < count($my_array ); $i ++)
print( "Element $i is $my_array[$i] " );

PRINTING THE ARRAY ELEMENTS
USING foreach LOOP
foreach loop works only on arrays, and is used to loop through each key/value
pair in an array.
Syntax:
14
$my_array = [0, 1, 2];
foreach( $my_array as $value)
print("$value ");
foreach ($array as $value){
code to be executed;
}

ACCESSING, ADDING AND
CHANGING AN ELEMENT
 To access individual elements in an array use location index
 To add elements to the end of an array
15
$my_array = ["tic", "tac", "toe"];
echo $my_array[1];
$string_array=["element1","element2"];
$string_array[] = "element3";
echo implode(", ", $string_array);
tac
element1, element2, element3
outpu
t
outpu
t

ACCESSING, ADDING AND
CHANGING AN ELEMENT
 To change or reassign individual elements in an array use location
index
16
$string_array = ["element 1", "element 2", "element 3"];
$string_array[0] = "NEW! different first element";
echo $string_array[0];
echo implode(", ", $string_array);
NEW! different first element
outpu
t
outpu
t NEW! different first element, second element, third element

array_pop( ) function
 It removes the last element of an
array
 It has one argument only
 takes an array as its argument.
 it returns the removed element.
array_push( ) function
 It add elements to the end of an array
 It has two arguments
 first argument is the array.
 second argument are the elements to be
added to the end of the array
 it returns the new number of elements in
the array.
17
PUSHING AND POPPING
METHODS
$my_array = ["tic", "tac", "toe"];
array_pop($my_array);
// $my_array is now ["tic", "tac"]
$popped = array_pop($my_array);
// $popped is "tac "
// $my_array is now ["tic"]
$new_array = ["eeny"];
$num_added = array_push($new_array,
"meeny", "miny", "moe");
echo $num_added; // Prints: 4
echo implode(", ", $new_array);
// Prints: eeny, meeny, miny, moe
end

array_shift() function
 It removes the first element of an array
 It has one argument only
 takes an array as its argument.
 Each of the elements in the array will be
shifted down an index.
 it returns the removed element.
array_unshift() function
 It add elements to the beginning of an array
 It has two arguments:
 first argument is the array.
 second argument are the elements to be
added to the beginning of the array
 returns the new number of elements in the
array.
18
SHIFTING AND UNSHIFTING
METHODS
$adjectives=["bad", "good",
"great", "fantastic"];
$removed=array_shift($adjectives);
echo $removed; //Prints: bad
echo implode(", ", $adjectives);
// Prints: good, great, fantastic
$foods = ["pizza", "crackers", "apples",
"carrots"];
$arr_len = array_unshift($foods, "pasta",
"meatballs", "lettuce");
echo $arr_len; //Prints: 7
echo implode(", ", $foods);
/* Prints: pasta, meatballs, lettuce,
pizza, crackers, apples, carrots */
start

ARRAY TYPES
19
Nested Array:
Associative Array:

NESTED ARRAYS
We mentioned that arrays can hold elements of any type—this
even includes other arrays!
We can use chained operations to access and change elements
within a nested array
20
$nested_arr = [[2 , 4] , [3 , 9] , [4 , 16]];
$first_el = $nested_arr[0][0];
echo $first_el;
outpu
t 2

NESTED ARRAYS PRACTICE
21
Let’s breakdown the steps:
•We need the outermost array first: $very_nested[3] evaluates to the array ["cat", 6.1, [9,
"LOST!", 6], "mouse"]
•Next we need the array located at the 2nd location index: $very_nested[3][2] evaluates to the
array [9, "LOST!", 6]
•And finally, the element we’re looking for: $very_nested[3][2][1] evaluates to "LOST!"
$very_nested=[ 1 , "b“ , 33 , [ "cat", 6.1, [ 9 , "LOST!" , 6] , "mouse“ ] ,
7.1 ];
In the given array, change the element "LOST!" to "Found!".
$very_nested[3][2][1] = "Found!";
$very_nested=[ 1 , "b“ , 33 , [ "cat", 6.1, [ 9 , "Found!" , 6] , "mouse“ ]
, 7.1 ];

ARRAY TYPES
22
Nested Array:
Associative Array:

ASSOCIATIVE ARRAYS
 Associative arrays are collections of key=>value pairs.
 The key in an associative array must be either a string or an integer.
 The values held can be any type. We use the => operator to associate a key
with its value.
23
$my_array = ["panda" => "very cute", "lizard" =>
"cute", "cockroach" => "not very cute"];
$my_array['panda'] = "very cute";
$my_array['lizard'] = "cute";
$my_array['cockroach'] = "not very cute";
OR

ASSOCIATIVE ARRAYS
24
$about_me = array(
"fullname" => "Aseel Amjad",
"social" => 123456789
);
We can also build associative arrays using the PHP array() function.
To print Associative Arrays it is just like the numeric array
use print_r() or implode() function

PRINTING ASSOCIATIVE ARRAYS
USING for LOOP
 To do so many functions are needed:
1. reset function: sets the internal pointer to the first array element.
2. key function: returns the index of the element currently referenced by the
internal pointer.
3. next function: moves the internal pointer to the next element.
25
$about_me = array( "fullname" => "Aseel Amjad",
"social" => 123456789);
for(reset($about_me); $element= key($about_me);next($about_me))
print( " $element is $about_me [$element] " );
Could you
predict the
output?

PRINTING ASSOCIATIVE ARRAYS
USING foreach LOOP
 foreach loop statement, designed for iterating through arrays especially
associative arrays, because it does not assume that the array has
consecutive integer indices that start at 0.
26
$about_me = array( "fullname" => "Aseel Amjad",
"social" => 123456789);
foreach ($about_me as $element => $value )
print( " $element is $value " );
Could you
predict the
output?

JOINING ARRAYS (+)
27
PHP also lets us combine arrays. The union (+) operator takes two array
operands and returns a new array with any unique keys from the second array
appended to the first array.
$my_array = ["panda" => "very cute", "lizard" => "cute",
"cockroach" => "not very cute"];
$more_rankings = ["capybara" => "cutest", "lizard" => "not
cute", "dog" => "max cuteness"];
$animal_rankings = $my_array + $more_rankings;
implode(", ", $animal_rankings)
since "lizard" is not a unique key, $animal_rankings["lizard"] will
retain the value of $my_array["lizard"] (which is "cute").
union (+)
operator
wouldn’t
work with
numerical
(ordered)
array …
why?
very cute, cute, not very cute, cutest, max cuteness
outpu
t

QUESTION
 What does the following code return?
$arr = array(1,3,5);
$count = count($arr);
if ($count == 0)
echo "An array is empty.";
else
echo "An array has $count elements.";
28

REVIEW
29
•In PHP, we refer to this data structure as ordered arrays.
•The location of an element in an array is known as its index.
•The elements in an ordered array are arranged in ascending numerical order
starting with index zero.
•We can construct ordered arrays with a built-in PHP function: array().
•We can construct ordered arrays with short array syntax, e.g. [1,2,3].
•We can print arrays using the built-in print_r() function or by converting them
into strings using the implode() function.
•We use square brackets ([]) to access elements in an array by their index.
•We can add elements to the end of an array by appending square brackets ([])
to an array variable name and assigning the value with the assignment operator
(=).
•We can change elements in an array using array indexing and the assignment
operator.

REVIEW
30
 The array_pop() function removes the last element of an array.
 The array_push() function adds elements to the end of an array.
 The array_shift() function removes the first element of an array.
 The array_unshift() function adds elements to the beginning of the array.
 We can use chained square brackets ([]) to access and change elements within a nested
array.
 Associative arrays are data structures in which string or integer keys are associated with
values.
 We use the => operator to associate a key with its value. $my_array = ["panda"=>"very cute"]
 To print an array’s keys and their values, we can use the print_r() function.
 We access the value associated with a given key by using square brackets ([ ]).
 We can assign values to keys using this same indexing syntax and the assignment operator (=):
$my_array["dog"] = "good cuteness";
 This same syntax can be used to change existing elements. $my_array["dog"] = "max
cuteness";
 In PHP, associative arrays and ordered arrays are different uses of the same data type.
 The union (+) operator takes two array operands and returns a new array with any unique keys
from the second array appended to the first array.

USEFUL
VIDEOS
SOURCE
ABOUT ARRAY
 45: What are arrays used for in PHP - PHP tutorial
 46: Insert data into array in PHP - PHP tutorial
 48: Different types of array in PHP - PHP tutorial
 49: What are associative arrays in PHP - PHP
tutorial
 50: What are multidimensional arrays in PHP - PHP
tutorial
Please refer for the given videos
links if needed
31

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