In this section, we will cover the basic syntax of PHP and how to work with variables. Understanding these fundamentals is crucial as they form the foundation for writing PHP scripts.

PHP code is embedded within HTML using special tags. The most common tag is <?php ... ?>.

The echo statement is used to output text or variables to the browser.

Comments are used to explain code and are ignored by the PHP engine. PHP supports single-line and multi-line comments.

Variables in PHP are declared using the $ symbol followed by the variable name. Variable names are case-sensitive and must start with a letter or an underscore.

PHP is a loosely typed language, meaning you do not need to declare the data type of a variable. PHP automatically converts the variable to the correct data type based on its value.

Examples:

• String: A sequence of characters.

  <?php
    $stringVar = "Hello, World!";
  ?>
  

• Integer: A non-decimal number.

  <?php
    $intVar = 42;
  ?>
  

• Float: A number with a decimal point.

  <?php
    $floatVar = 3.14;
  ?>
  

• Boolean: Represents two possible states: true or false.

  <?php
    $boolVar = true;
  ?>
  

• Array: A collection of values.

  <?php
    $arrayVar = array("apple", "banana", "cherry");
  ?>
  

• Object: An instance of a class.

  <?php
    class Car {
      function Car() {
        $this->model = "VW";
      }
    }
    $carVar = new Car();
  ?>
  

The scope of a variable determines where it can be accessed within the code. PHP has three main types of variable scope:

• Local Scope: Variables declared within a function are local to that function.

  <?php
    function myFunction() {
      $localVar = "I'm local";
      echo $localVar;
    }
    myFunction();
    // echo $localVar; // This will cause an error
  ?>
  

• Global Scope: Variables declared outside of any function have a global scope and can be accessed anywhere in the script.

  <?php
    $globalVar = "I'm global";
  
    function myFunction() {
      global $globalVar;
      echo $globalVar;
    }
    myFunction();
  ?>
  

• Static Scope: Static variables retain their value even after the function has completed.

  <?php
    function myFunction() {
      static $staticVar = 0;
      echo $staticVar;
      $staticVar++;
    }
    myFunction(); // Outputs: 0
    myFunction(); // Outputs: 1
    myFunction(); // Outputs: 2
  ?>
  

Declare variables for your name, age, and favorite color. Output these variables in a sentence.

Solution:

Create an array of three of your favorite movies. Output the list in a sentence.

Solution:

• Uninitialized Variables: Always initialize your variables before using them to avoid unexpected results.
• Case Sensitivity: Remember that variable names are case-sensitive. $Var and $var are different variables.
• Concatenation: Use the . operator to concatenate strings in PHP.

In this section, we covered the basics of PHP syntax and variables. You learned how to declare variables, understand their types, and use them within your scripts. These fundamentals are essential as you progress to more complex topics in PHP. Next, we will explore control structures, which allow you to control the flow of your PHP scripts.