PHP Foreach Loops

foreach iterates arrays and Traversable objects by value or reference.

What It Does

foreach iterates arrays and Traversable objects by value or reference. The following examples distinguish a normal use case, a boundary case and a practical application.

Requirements and Compatibility

PHP 8.x and a local test environment. Apply input validation, correct error handling and the requirements of any optional libraries.

The code focuses on the core concept. Production implementation may also need routes, validation, persistence, authorization or deployment tooling.

Example 1: Basic Behavior

Start with the smallest meaningful working case.

<?php
foreach (['red', 'blue'] as $color) { echo $color . ' '; }

Example 2: Another Case

Examine the edge case and the observable result.

<?php
foreach (['alex' => 12, 'mira' => 15] as $name => $points) { echo $name . ':' . $points . ' '; }

Practical Example: Putting It to Use

Apply the technique to a small practical task.

<?php
$scores = [10, 12];
foreach ($scores as &$score) { $score += 5; }
unset($score);
print_r($scores);

Important Behavior and Edge Cases

Unset reference variables after a foreach-by-reference to avoid accidental later mutation.

Comparison with Related Functions or Approaches

Common Beginner Mistakes

Key Takeaways

• foreach iterates arrays and Traversable objects by value or reference.
• Unset reference variables after a foreach-by-reference to avoid accidental later mutation.
• Use for when an index-driven counter is necessary.

Before adapting these examples, verify the return values, test the failure paths and confirm that your application meets its security and environment requirements.