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JAVASCRIPTHTMLCSSPYTHONSQLJAVACPPCSHARPPHPTYPESCRIPTCRUBYGOSWIFTKOTLINRUSTRBASHSCALAOBJECTIVE-CDARTPERLLUAMATLABXMLJSONMARKDOWNASSEMBLYLATEXYAMLSOLIDITYBLOCKCHAIN

Topics

PHP Basics

Introduction to PHPInstalling PHPPHP SyntaxPHP CommentsPHP VariablesPHP Echo / PrintPHP Data TypesPHP StringsPHP NumbersPHP ConstantsPHP OperatorsPHP If...Else...ElseifPHP SwitchPHP LoopsPHP FunctionsPHP ArraysPHP Superglobals

PHP Forms

PHP Form HandlingPHP Form ValidationPHP Form RequiredPHP Form URL/E-mailPHP Form Complete

PHP Advanced

PHP Date and TimePHP IncludePHP File HandlingPHP File Open/ReadPHP File Create/WritePHP File UploadPHP CookiesPHP SessionsPHP FiltersPHP Filters AdvancedPHP Callback FunctionsPHP JSONPHP Exceptions

PHP OOP

PHP OOP IntroPHP Classes/ObjectsPHP ConstructorPHP DestructorPHP Access ModifiersPHP InheritancePHP ConstantsPHP Abstract ClassesPHP InterfacesPHP TraitsPHP Static MethodsPHP Static PropertiesPHP NamespacesPHP Iterables

PHP Database

PHP MySQL DatabasePHP Connect to MySQLPHP Create MySQL DatabasePHP Create MySQL TablePHP Insert MySQL DataPHP Get Last Inserted IDPHP Insert Multiple RecordsPHP Prepared StatementsPHP Select MySQL DataPHP Delete MySQL DataPHP Update MySQL DataPHP Limit MySQL Data

PHP XML

PHP XML ParsersPHP SimpleXML ParserPHP SimpleXML - GetPHP XML ExpatPHP XML DOM

PHP Security

PHP SecurityPHP Password HashingPHP E-mail InjectionPHP Cross Site Scripting (XSS)

PHP Best Practices

PHP Coding StandardsPHP Error HandlingPHP Performance OptimizationPHP Debugging TechniquesPHP Unit Testing

PHP and Web Services

PHP AJAX IntroductionPHP AJAX PHPPHP AJAX DatabasePHP AJAX XMLPHP AJAX Live SearchPHP AJAX Poll

PHP Extensions

PHP cURLPHP GDPHP XML-RPCPHP Multibyte String

PHP Syntax: The Foundation of PHP Programming

PHP syntax forms the backbone of PHP programming. It defines the rules for writing PHP code that can be interpreted and executed by the PHP engine. Understanding PHP syntax is crucial for creating functional and efficient web applications.

Basic PHP Structure

PHP code is typically enclosed within special tags. The most common tag pair is:

<?php
// Your PHP code here
?>

Alternatively, you can use the short echo tag for quick output:

<?= "Hello, World!" ?>

Statements and Semicolons

In PHP, each statement should end with a semicolon (;). This tells the PHP interpreter that the statement is complete. For example:

<?php
$name = "John";
echo "Hello, " . $name;
?>

Comments in PHP

Comments are crucial for code readability. PHP supports both single-line and multi-line comments:

<?php
// This is a single-line comment

/*
This is a
multi-line comment
*/

echo "Comments are not executed"; // Inline comment
?>

PHP and HTML Integration

One of PHP's strengths is its seamless integration with HTML. You can switch between PHP and HTML easily:

<!DOCTYPE html>
<html>
<body>
    <h1>Welcome</h1>
    <?php
    $greeting = "Hello, PHP!";
    echo "<p>$greeting</p>";
    ?>
</body>
</html>

Case Sensitivity

In PHP, keywords (like if, else, while, echo, etc.), classes, and functions are not case-sensitive. However, variable names are case-sensitive. For instance:

<?php
$color = "red";
ECHO $color; // Works
echo $COLOR; // Doesn't work (variables are case-sensitive)
?>

Best Practices for PHP Syntax

  • Always close PHP tags to prevent unexpected output
  • Use consistent indentation for better readability
  • Follow a coding standard like PSR-12 for consistent code style
  • Use meaningful variable and function names
  • Keep your code DRY (Don't Repeat Yourself)

Related Concepts

To deepen your understanding of PHP syntax, explore these related topics:

Mastering PHP syntax is the first step towards becoming a proficient PHP developer. As you progress, you'll discover how these fundamental rules combine to create powerful web applications.