PHP: The Ultimate Guide

405 Pages·2022·6.433 MB·English

by  Sufyan bin Uzayr

PHP
There is no shortage of websites that use the PHP programming language in some
or other capacity. PHP (Hypertext Preprocessor) is a server-side scripting lan-
guage that allows you to create dynamically-generated web pages. Rasmus Lerdorf
created PHP in 1994.
PHP works in the backend of a website because it is a server-side technology. This is
the part of a website that no one sees. This means that PHP is frequently used to run
server-side programs such as data collection and processing and database manage-
ment. The fact that PHP is a simple language is one of the key reasons why learning
it is a wise investment. PHP was created with the goal of speeding up web develop-
ment; therefore, it features a basic syntax that is ideal for beginners. Furthermore,
because PHP is a dynamically typed language, there are less restrictions to follow
while creating features. The PHP programming language offers a wide range of ap-
plications and features, such as authentication, payments, user administration, and
other “dynamic” aspects of a website.
Efficiency, syntax compatibility, platform independence, error detection, and en-
cryption are just a few of the interesting properties of PHP.
Why should you learn PHP? PHP developers work with the PHP programming
language to create websites, applications, and programs. As a PHP developer, you’ll
usually be working in IT companies (all over the world), but there are also a lot of
opportunities in design and business. A PHP developer, like any other program-
ming/scripting language developer, should be able to work with many languages
and ideally have some knowledge of database, web design, or some page format-
ting language.
This book offers:
• A step-by-step approach to problem solving and skill development
• A quick run-through of the basic concepts, in the form of a “Crash Course”
• Advanced, hands-on core concepts, with a focus on real-world problems
• Industry-level coding paradigms and a practice-oriented explanatory
approach
• Special emphasis on writing clean and optimized code, with additional
chapters focused on coding methodology
PHP
The Ultimate Guide
Sufyan bin Uzayr
First edition published 2023
by CRC Press
6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742
and by CRC Press
4 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN
CRC Press is an imprint of Taylor & Francis Group, LLC
© 2023 Sufyan bin Uzayr
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Library of Congress Cataloging-in-Publication Data
Names: Bin Uzayr, Sufyan, author.
Title: PHP : the ultimate guide / Sufyan bin Uzayr.
Description: First edition. | Boca Raton : CRC Press, 2023. | Includes
bibliographical references and index.
Identifiers: LCCN 2022025685 (print) | LCCN 2022025686 (ebook) |
ISBN 9781032312224 (hardback) | ISBN 9781032311784 (paperback) |
ISBN 9781003308669 (ebook)
Subjects: LCSH: PHP (Computer program language) | Web site development.
Classification: LCC QA76.73.P224 B56 2023 (print) | LCC QA76.73.P224 (ebook) |
DDC 005.2/762--dc23/eng/20220919
LC record available at https://lccn.loc.gov/2022025685
LC ebook record available at https://lccn.loc.gov/2022025686
ISBN: 9781032312224 (hbk)
ISBN: 9781032311784 (pbk)
ISBN: 9781003308669 (ebk)
DOI: 10.1201/9781003308669
Typeset in Minion
by KnowledgeWorks Global Ltd.
Contents
Acknowledgments, xxi
About the Author, xxiii
Chapter 1 ◾ I ntroduction to PHP 1
HISTORY 2
WHY DO WE LEARN PHP? 2
VERSIONS OF PHP 2
PHP 4
What Is PHP? 4
What Can We Do with PHP? 4
Main Components 5
Pros and Cons of PHP 6
Built-in Templating Engine 8
PHP from the Command Line 9
Upgrading PHP in macOS 11
Upgrading PHP in Windows 11
Upgrading PHP in Ubuntu 11
Why Is PHP Still So Widely Used? 12
PHP Prerequisites 13
INSTALLATION OF PHP 13
How to Install PHP on Windows 13
How to Install PHP on Linux 13
Installing PHP on Ubuntu 14
How to Install PHP on macOS 14
v
vi ◾ Contents
Installing a Text Editor 15
Starting Apache to Run PHP Scripts 15
Place Your Project in the Root Directory of XAMPP 15
Printing Hello PHP on the Web Browser with a PHP File 16
PHP Hello World on the Command Line 16
PHP BASICS 17
Naming Conventions for PHP Variables 19
Echo Statement 22
Displaying Strings with the Print Statement 23
WHAT IS HTML (HYPERTEXT MARKUP LANGUAGE BASICS)? 24
Most Used HTML Tags and HTML Elements 25
Block-Level Elements 25
Inline Elements 25
Using PHP and HTML on a Single Page 26
CSS (CASCADING STYLE SHEETS) 27
What Is CSS? 27
CSS Syntax 27
Using CSS with PHP 28
Data Types 29
Chapter 2 ◾ D ata Types and Operators 43
CODING BUILDING BLOCKS 43
VARIABLES 44
Reading a Variable’s Value 44
Types of Variables 46
PREDEFINED VARIABLES 48
IS PHP A CASE-SENSITIVE LANGUAGE? 49
REGULAR EXPRESSION 50
Why Does Perl Style Regular Expressions? 50
Regular Expression Syntax 51
Character Classes in Regular Expression 51
Contents ◾ vii
Built-in Regular Expression Functions in PHP 51
Regular Expression Metacharacters 53
DATA TYPES 53
What Is a Data Type? 53
Integers 55
Strings 55
WHAT IS PHP’S STRING FUNCTION? 56
String Functions 57
ESCAPE SEQUENCES 60
FLOATING POINT NUMBERS OR DOUBLES 61
Booleans 61
Arrays 62
Operator Keywords 66
Objects 66
NULL 67
Resources 67
Typecasting 68
Automatic Type Conversion 70
IMPLICIT AND EXPLICIT CASTING 70
EXPRESSIONS 70
Expressions with ++ and −− Operators 71
Expressions with Ternary Conditional Operator 71
OPERATORS 72
CHAPTER SUMMARY 86
Chapter 3 ◾ C ontrol Statements 87
INTRODUCTION TO CONTROL STATEMENTS 87
LIST OF KEYWORDS AVAILABLE IN PHP 89
What Is a Keyword? 89
Operands Lvalue and Rvalue 90
Lvalue 90
Rvalue 90
viii ◾ Contents
LIST OF CONTROL STATEMENTS 91
The if Statement 91
The else Statement 91
else-if Statement 92
switch Statement 93
The ? Operator 95
Expressions with the Ternary Conditional Operator 95
Alternative Syntax for Control Structures (if, else-if) 96
while Loop 96
do-while Loop 98
for Loop 98
Breaking Out of the Loop 99
foreach 100
Continue 101
Break and Continue in while Loops 101
match 102
declare 103
return Statement 104
require Statement 104
include Statement 104
require_once Statement 105
include_once Statement 105
goto Operator 106
WHAT IS THE BOOLEAN EXPRESSION IN PHP? 106
Boolean Constant 106
CHAPTER SUMMARY 106
Chapter 4 ◾ P HP Functions 107
FUNCTIONS 107
DECLARING A FUNCTION 108
function return Statement 109
function with Default Argument Value 110
Contents ◾ ix
The function within Another function 110
The return Statement 111
Scope and the Global Statement 112
Working with print_r() 113
How to Pass PHP Variables by Reference 114
Pass by Reference 115
VARIABLE-LENGTH ARGUMENT FUNCTION 115
Built-in Functions in PHP 116
Recursion 117
Dynamic Function Calls 118
Callable 119
TYPES OF FUNCTIONS 119
Language Constructs 122
Function Handling Functions 123
Flag Parameters 125
INTRODUCTION TO PHP USER DEFINED FUNCTIONS 126
Namespace PHP Functions 126
PHP KEYWORDS AND IDENTIFIERS TUTORIAL 128
What Is an Identifier? 128
Rules for Naming Identifiers 128
Identifier Casing Conventions 130
TYPE HINTS 131
How to Use Array-Type Hinting 131
How to Use Object-Type Hinting 132
Does PHP Support Any Type Hinting for Some Basic Data Types? 133
THE SPLAT OPERATOR IN PHP 133
SIGNATURE 134
“PARAMETER” VS. “ARGUMENT” 135
Variable Functions 136
Anonymous Functions (Lambda) 137
Assigning the Anonymous Function to Variables 138
Using an Anonymous Function as the Callback 138