Control structures in PHP allow you to control the flow of execution in your code. They enable you to make decisions based on certain conditions and repeat blocks of code as needed. In this section, we'll explore the different types of control structures available in PHP.

Conditional Statements

Conditional statements allow you to execute different blocks of code based on whether a specific condition is true or false.

If Statement

The if statement is the most basic conditional statement in PHP. It evaluates a given condition and executes a block of code if the condition is true.

if (condition) {
    // Code to be executed if the condition is true
}

You can optionally include an else clause to specify a block of code to be executed if the condition is false.

if (condition) {
    // Code to be executed if the condition is true
} else {
    // Code to be executed if the condition is false
}

You can also use the elseif clause to chain multiple conditions together.

if (condition1) {
    // Code to be executed if condition1 is true
} elseif (condition2) {
    // Code to be executed if condition2 is true
} else {
    // Code to be executed if both conditions are false
}

Switch Statement

The switch statement is an alternative to using multiple if...elseif...else statements. It evaluates a single expression and executes the associated block of code based on different possible values.

switch (expression) {
    case value1:
        // Code to be executed if expression matches value1
        break;
    case value2:
        // Code to be executed if expression matches value2
        break;
    // ...
    default:
        // Code to be executed if no case matches
}

The break statement is used to exit the switch block once a matching case is found. If no break is present, execution will continue to the next case.

Loops

Loops allow you to repeatedly execute a block of code as long as a certain condition is true. PHP provides several types of loops:

While Loop

The while loop executes a block of code as long as a specified condition is true.

while (condition) {
    // Code to be executed
}

Do-While Loop

The do-while loop is similar to the while loop, but it executes the code block at least once, even if the condition is false.

do {
    // Code to be executed
} while (condition);

For Loop

The for loop is commonly used when you know the number of iterations in advance. It combines the initialization, condition, and increment/decrement expressions into a single line.

for (initialization; condition; increment/decrement) {
    // Code to be executed
}

Foreach Loop

The foreach loop is specifically designed to iterate over arrays or objects. It provides an easy way to access each value in the collection.

// Iterating over an array
foreach ($array as $value) {
    // Code to be executed
}

// Iterating over an associative array
foreach ($array as $key => $value) {
    // Code to be executed
}

Breaking and Continuing Loops

PHP provides two control statements that allow you to alter the flow of a loop:

  • break: Terminates the current loop and transfers control to the statement immediately following the loop.
  • continue: Skips the current iteration of the loop and moves to the next iteration.

Alternative Control Structures

In addition to the traditional control structures, PHP also provides alternative syntax for some of them:

  • if/elseif/else: ?: ternary operator
  • while: endwhile
  • for: endfor
  • foreach: endforeach
  • switch: endswitch

These alternative syntaxes can make your code more readable in certain situations, but their usage is optional.

In the next section, we'll explore functions in PHP, which allow you to encapsulate reusable blocks of code and promote code organization and maintainability.