The document provides an overview of PHP arrays, detailing the three types: indexed, associative, and multidimensional arrays, along with examples of their creation and manipulation. It covers how to access elements, loop through arrays using various methods, and demonstrates string manipulation functions in PHP, such as calculating length, counting words, and replacing text. Additionally, the document illustrates using escape sequences within strings and provides coding examples for practical understanding.

1. PHP ARRAYS

2. PHP arrays
• Arrays are complex variables that allow us to store more
than one value or a group of values under a single
variable name.

3. Types of Arrays in PHP
There are three types of arrays that you can create. These
are:
• Indexed array — An array with a numeric key.
• Associative array — An array where each key has its
own specific value.
• Multidimensional array — An array containing one or
more arrays within itself.

4. Indexed Arrays
• An indexed or numeric array stores each array element with a
numeric index.
<?php
$courses = array("PHP", "Laravel", "Node js");
echo "I like " . $courses[0] . ", " . $courses[1] . " and " . $courses[2];
echo "<br>";
echo count($courses);
?>
OUTPUT:
I like PHP, Laravel and Node js
3

5. Loop Through an Indexed Array(for loop)
<?php
$courses = array("PHP", "Laravel", "Node js");
$courseslength = count($courses);
for($x = 0; $x <$courseslength; $x++) {
echo $courses[$x];
echo "<br>";
}
?>
OUTPUT:
PHP
Laravel
Node js

6. Loop Through an Indexed Array(PHP foreach
Loop)
• The foreach loop is used to iterate over arrays.
• It is used to loop through each key/value pair in an array.
<?php
$courses = array("PHP", "Laravel", "Node js");
// Loop through colors array
foreach($courses as $course){
echo $course . "<br>";
}
?>
OUTPUT:
PHP
Laravel
Node js

7. Associative Array
• Associative arrays are arrays that use named keys that
you assign to them.
• We can associate name with each array elements in PHP
using => symbol.
• The keys assigned to values can be arbitrary and user
defined strings.

8. Associative Array(contd.)
<?php
$courses = array("INT220"=>"PHP", "INT221"=>"Laravel",
"INT222"=>"Node js");
echo "INT 220 is ".$courses['INT220'].". INT 221 is ".
$courses['INT221'].". INT222 is ".$courses['INT222'];
?>
OUTPUT:
INT 220 is PHP. INT 221 is Laravel. INT222 is Node js

9. Associative Array(contd.)
<?php
$courses["INT220"] = "PHP";
$courses["INT221"] = "Laravel";
$courses["INT222"] = "Node js";
// Printing array structure
print_r($courses);
?>
OUTPUT:
Array ( [INT220] => PHP [INT221] => Laravel [INT222] =>
Node js )

10. Loop Through an Associative Array(for each
loop)
<?php
$courses =
array("INT220"=>"PHP","INT221"=>"Laravel","INT222"=>"Node
js");
foreach($courses as $course => $value) {
echo "Key=".$course.","."Value=".$value;
echo "<br>";
}
?>
OUTPUT:
Key=INT220, Value=PHP
Key=INT221, Value=Laravel
Key=INT222, Value=Node js

11. Loop Through an Associative Array(for loop)
<?php
$courses = array('INT220'=>'PHP','INT221'=>'Laravel','INT222'=>'N
ode js');
$keys = array_keys($courses);
$values = array_values($courses);
for($x=0; $x<count($courses); $x++) {
echo "Key=".$keys[$x].','."Value=".$values[$x]. "<br>";
}
?>
OUTPUT:
Key=INT220,Value=PHP
Key=INT221,Value=Laravel
Key=INT222,Value=Node js

12. Multidimensional Arrays
• The multidimensional array is an array in which each
element can also be an array and each element in the
sub-array can be an array or further contain array within
itself and so on.

13. Multidimensional Arrays(contd.)
<?php
$result = array(
array("Manoj",7.8,"pass"),
array("Aditya",8.5,"pass"),
array("Anuj",4.9,"fail")
);
echo $result[0][0]. "----CGPA is: " . $result[0][1]." and his status is ".
$result[0][2]."<br>";
echo $result[1][0]. "----CGPA is: " . $result[1][1]." and his status is ".
$result[1][2]."<br>";
echo $result[2][0]. "----CGPA is: " . $result[2][1]." and his status is ".
$result[2][2];
?>
OUTPUT:
Manoj----CGPA is: 7.8 and his status is
pass
Aditya----CGPA is: 8.5 and his status is
pass
Anuj----CGPA is: 4.9 and his status is fail

14. Multidimensional Arrays(contd.)
<?php
$result = array(
array(
"name" => "Manoj",
"cgpa" => 7.8,
"status" => "pass"
),
array(
"name" => "Aditya",
"cgpa" => 8.5,
"status" => "pass"
),
array(
"name" => "Anuj",
"cgpa" => 4.9,
"status" => "fail"
)
);
echo $result[0]["name"]. "----CGPA is: " . $result[0]["cgpa"]." and his status is ".$result[0]["status"]."<br>";
echo $result[1]["name"]. "----CGPA is: " . $result[1]["cgpa"]." and his status is ".$result[1]["status"]."<br>";
echo $result[2]["name"]. "----CGPA is: " . $result[2]["cgpa"]." and his status is ".$result[2]["status"];
?>
OUTPUT:
Manoj----CGPA is: 7.8 and his status is pass
Aditya----CGPA is: 8.5 and his status is pass
Anuj----CGPA is: 4.9 and his status is fail

15. Loop Through an Multidimensional Array(for
loop)
<?php
$result = array (
array("Manoj",7.8,"pass"),
array("Aditya",8.5,"pass"),
array("Anuj",4.9,"fail")
);
for ($row = 0; $row < 3; $row++) {
echo "<h4>Row number $row</h4>";
for ($col = 0; $col < 3; $col++) {
echo $result[$row][$col]."<br>";
}
}
?>
OUTPUT:
Row number 0
Manoj
7.8
Pass
Row number 1
Aditya
8.5
Pass
Row number 2
Anuj
4.9
fail

16. Loop Through an Multidimensional Array(foreach
loop)
<?php
$result = array (
array("Manoj",7.8,"pass"),
array("Aditya",8.5,"pass"),
array("Anuj",4.9,"fail")
);
for($row = 0; $row < 3; $row++) {
echo "<h4>Row number $row</h4>";
foreach ($result[$row] as $resul) {
echo $resul."<br>";
}
}
?>
OUTPUT:
Row number 0
Manoj
7.8
Pass
Row number 1
Aditya
8.5
Pass
Row number 2
Anuj
4.9
fail

17. Loop Through an Multidimensional Array(foreach
loop)
<?php
$books =
array("C++" => array("name" => "Beginning with C","copies" =>8),
"PHP" => array("name" => "Basics of PHP","copies" => 10),
"Laravel" => array("name" => "MVC","copies" => 3)
);
$keys = array_keys($books);
for($i = 0; $i < count($books); $i++) {
echo "<h1>$keys[$i]</h1>";
foreach($books[$keys[$i]] as $key => $value) {
echo $key . " = " . $value . "<br>";
}
}
?>
C++
name = Beginning with C
copies = 8
PHP
name = Basics of PHP
copies = 10
Laravel
name = MVC
copies = 3

18. Strings
• A string is a sequence of letters, numbers, special
characters and arithmetic values or combination of all.
• The simplest way to create a string is to enclose the string
literal (i.e. string characters) in single quotation marks ('),
like this: $str= “Hello World”;
• The escape-sequence replacements are:
• n is replaced by the newline character
• r is replaced by the carriage-return character
• t is replaced by the tab character
• $ is replaced by the dollar sign itself ($)
• " is replaced by a single double-quote (")
• is replaced by a single backslash ()

19. String(contd.)
<?php
$my_str = 'World';
echo "Hello, $my_str!<br>";
echo 'Hello, $my_str!<br>';
echo '<pre>HellotWorld!</pre>';
echo "<pre>HellotWorld!</pre>";
echo 'I'll be back';
?>
Output:
Hello, World! //(followed by a line break)
Hello, $my_str! // (no variable interpolation, followed by the literal text)
HellotWorld! //(displayed as written because it's in <pre> tags with single
quotes)
Hello World! //(with a tab space in between because it's in <pre> tags with
double quotes)
I'll be back //(single quote properly escaped)

20. Manipulation PHP Strings
• PHP provides many built-in functions for manipulating strings like
calculating the length of a string, find substrings or characters,
replacing part of a string with different characters, take a string
apart, and many others.
1.Calculating the Length of a String
• The strlen() function is used to calculate the number of characters
inside a string. It also includes the blank spaces inside the string.
<?php
$my_str = 'Welcome to PHP';
// Calculating and displaying string length
echo strlen($my_str);
?>
Output: 14

21. String(contd.)
2. Counting Number of Words in a String
The str_word_count() function counts the number of words
in a string.
<?php
$my_str = 'The quick brown fox jumps over the lazy
dog.';
// Calculating and displaying number of words
echo str_word_count($my_str);
?>
Output: 9

22. String(contd.)
• 3. Replacing Text within Strings
The str_replace() replaces all occurrences of the search
text within the target string.
<?php
$my_str = 'If the facts do not fit the theory, change the
facts.';
// Display replaced string
echo str_replace("facts", "truth", $my_str);
?>
Output: If the truth do not fit the theory, change the truth.

23. Contd.
• You can optionally pass the fourth argument to
the str_replace() function to know how many times the
string replacements was performed like this:
<?php
$my_str = 'If the facts do not fit the theory, change the
facts.';
// Perform string replacement
str_replace("facts", "truth", $my_str, $count);
// Display number of replacements performed
echo "The text was replaced $count times.";
?>
• Output: The text was replaced 2 times.

24. String(contd.)
4. Reversing a String
The strrev() function reverses a string.
<?php
$my_str = 'You can do anything, but not everything.';
// Display reversed string
echo strrev($my_str);
?>
Output: .gnihtyreve ton tub ,gnihtyna od nac uoY