The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →A practical use for recursion in PHP is searching a project directory for every .php file, including files several folders deep. PHP’s RecursiveDirectoryIterator exposes directory entries and child directories; RecursiveIteratorIterator walks that nested structure for you.
Why directory traversal is a good fit for recursion
A project directory has a tree-like shape: a folder can contain files and other folders, and each child folder can contain more of the same. Recursion fits this structure because the operation—inspect entries, then inspect child directories—repeats at every level. PHP’s RecursiveDirectoryIterator documentation uses finding PHP files in a directory tree as an example.
In a function written by hand, the base case would be reaching a directory with no more child directories to visit. With PHP’s SPL recursive iterators, the child relationship is represented by hasChildren() and getChildren(); the iterator machinery handles continuing the traversal.
Find PHP files under a project folder
This example prints the path of each PHP file found below a specified project directory:
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
<?php
$directory = new RecursiveDirectoryIterator(
'path/to/project',
FilesystemIterator::SKIP_DOTS
);
$files = new RecursiveIteratorIterator($directory);
foreach ($files as $file) {
if ($file->isFile() && $file->getExtension() === 'php') {
echo $file->getPathname(), PHP_EOL;
}
}- Set the root. Replace
path/to/projectwith the folder you intend to search. Keeping the scan rooted at the project avoids traversing an unspecified part of the filesystem. - Create the directory iterator.
RecursiveDirectoryIteratorsupplies entries and child iterators;FilesystemIterator::SKIP_DOTSskips the special.and..entries. - Wrap it for recursive traversal.
RecursiveIteratorIteratorconsumes recursive iterators and walks their nested structure. Its default mode is leaves-only, which suits collecting files. - Filter the results. The condition keeps entries that are files and whose extension is exactly
php; directories and other file types are ignored. - Use the paths. This example prints each matching pathname. In a project tool, the same loop could instead collect paths for another defined task.
The RecursiveIteratorIterator manual describes the class as something that “Can be used to iterate through recursive iterators.” The extension check here is a compact illustration; the official RecursiveDirectoryIterator example demonstrates selecting PHP files with a RegexIterator.
Choose traversal behavior deliberately
RecursiveIteratorIterator supports three traversal modes: leaves-only, self-first, and child-first. The default is leaves-only, so the example yields the files at the ends of the directory branches rather than returning directory entries as results. Self-first visits an entry before descending into its children; child-first descends before processing the parent entry. Choose a different mode only when the order or inclusion of directory entries matters to the task.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
The iterator also supports a maximum depth. A depth limit can make sense when a task is intentionally restricted to the project’s top-level folders, but it changes what the scan can find. Consult the class manual for the available mode and depth behavior.
Handle links, filters, and filesystem edge cases
Symbolic links
RecursiveDirectoryIterator::hasChildren() accepts an allowLinks argument, whose default is false. That setting matters when a project contains symbolic links: decide whether linked directories belong in the scan rather than assuming the traversal will follow them. See the iterator manual for the method’s behavior.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Restrict the scan
Filtering can serve two distinct purposes: limit which directories are descended into, and limit which files are returned. For example, a project-specific task might exclude generated or dependency directories. Apply directory filtering at the point where traversal decisions are made; filtering only the final output can still cause the scan to enter folders whose contents you do not need. PHP’s manual includes user-contributed notes showing callback-based filtering; these are user notes, not official PHP guidance.
Errors and unusual entries
Filesystem access can fail because a path is missing, permissions are insufficient, or entries change while a scan is running. The short example shows the traversal and file selection, not a complete error-handling policy. For a tool that must report every inaccessible path or continue after failures, decide how those exceptions and warnings should be handled and verify the relevant behavior against the PHP version and filesystem environment you support.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
SPL iterators or a recursive function?
Both approaches can express the same tree walk. SPL is concise for this task and directly models directory recursion with standard iterator classes. A hand-written recursive function can provide explicit control over how each directory is read, how results are shaped, and how errors are handled.
| Consideration | SPL recursive iterators | Hand-written recursive function |
|---|---|---|
| Clarity for this directory-search task | Pairs RecursiveDirectoryIterator with RecursiveIteratorIterator to traverse nested directories. |
Makes the repeated visit to each child directory explicit in your own code. |
| Control over returned data | Filter entries in the iteration loop or with iterator components. | Define exactly what each recursive call returns or records. |
| Filtering and traversal behavior | Uses iterator methods, traversal modes, depth, and filtering components. | Implements descent and filtering rules directly. |
| Error and unusual-entry handling | Requires a deliberate policy around iterator and filesystem behavior. | Can place custom handling directly around directory-reading and recursive calls. |
| Performance comparison | not stated (the official PHP iterator documentation does not establish a general winner) | not stated (the official PHP iterator documentation does not establish a general winner) |
Choose based on the control and readability your project needs. The official documentation supports the SPL approach for this example; it does not establish that SPL or a hand-written function is universally faster.
PC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Crashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteQuick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
When this pattern is useful
- Finding source files in a project with nested folders.
- Building a list of files for a defined project-level operation.
- Applying one consistent inspection rule to every directory level while keeping the search scope rooted in a known folder.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
