When working with PHP in PHP, it helps to understand exactly what scandir() does and when the result is useful. This guide uses small examples followed by a practical pattern.
What Is scandir() in PHP?
Returns directory entry names sorted ascending by default, including dot entries where exposed.
Syntax:
scandir(string $directory, int $sorting_order = ..., $context = ...) : array|false
Parameters:
$directory(string) is required.$sorting_order(int) is optional.$contextis optional.
Return value: PHP declares array|false for this API in PHP 8.4 where available. For operations that can fail, check errors or exceptions instead of assuming success.
Example 1: Basic Usage
The first example focuses on the operation itself without unrelated application logic.
<?php
print_r(scandir(__DIR__));
Returns directory entry names sorted ascending by default, including dot entries where exposed. The example demonstrates the API in an isolated teaching script. File paths, permissions and optional extensions may need adapting for a real project.
Example 2: Handling Conditions and Failures
Production code must handle cases where the archive, file, runtime feature, or source path is not available. The following example demonstrates an additional usage pattern.
<?php
print_r(scandir(__DIR__));
// Inspect and handle the result before using it.
Only catch errors you can handle meaningfully. A PHP warning, a false return value, and an exception are not interchangeable; consult the behavior explained above.
Practical Example: Integrating the Operation
This practical variation shows how to place the operation in a larger file or inspection workflow. The paths and names are illustrative rather than server deployment instructions.
<?php
function inspectEnvironment(): void
{
print_r(scandir(__DIR__));
}
inspectEnvironment();
Do not copy sample paths blindly into production. Validate allowed paths and confirm the appropriate extension and filesystem permissions first.
Important Behavior and Edge Cases
- Directory listings may contain dot entries, and ordering can be controlled by the sorting-order parameter.
- Never treat directory entry names as safe HTML or safe file paths without validation.
- Unreadable directories can raise warnings or exceptions depending on PHP version.
Comparison With Related Functions
| Function or Method | Purpose |
|---|---|
scandir | Returns directory entry names sorted ascending by default, including dot entries where exposed. |
file_get_contents() | Loads file contents into a string instead of directly streaming them. |
realpath() | Resolves a filesystem path instead of inspecting or changing a PHP setting. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Assuming filesystem state cannot change after a check. | Handle failures from the actual file operation. |
| Passing unchecked user paths into filesystem APIs. | Restrict paths to known directories and validate resolved destinations. |
| Displaying sensitive filesystem configuration to visitors. | Keep diagnostic output in restricted administrative tools. |
Key Takeaways
- Returns directory entry names sorted ascending by default, including dot entries where exposed.
- Directory listings may contain dot entries, and ordering can be controlled by the sorting-order parameter.
- Never treat directory entry names as safe HTML or safe file paths without validation.
scandir() is useful when its specific purpose matches your application. Keep the examples focused, respect the restrictions above, and validate real-world inputs rather than relying on the example values.