The PHP ArrayIterator::seek API performs a focused operation on an object or value. The examples below show its effect on actual data.
Moves the iterator to a requested numeric position; an invalid position can throw OutOfBoundsException.
What Is ArrayIterator::seek in PHP?
Moves the iterator to a requested numeric position; an invalid position can throw OutOfBoundsException.
Syntax:
ArrayIterator::seek(int $offset)The method accepts the following parameters:
$offset— Required. The key or numeric index of the entry being accessed in the collection.
Return type declared by PHP: mixed / not explicitly declared. The value or side effect is demonstrated in the examples below.
Example 1: Basic Usage
This example uses a small input to make the main behavior visible.
<?php
$arrayIterator = new ArrayIterator(["pear" => 4, "apple" => 2, "plum" => 9]);
$arrayIterator->seek(1);
var_dump($arrayIterator->current());Output:
int(2)Moves the iterator to a requested numeric position; an invalid position can throw OutOfBoundsException.
Example 2: A Different Input
A different set of values shows the same operation in another situation.
<?php
$arrayIterator = new ArrayIterator(["first" => "draft", "second" => "ready", "third" => "done"]);
$arrayIterator->seek(1);
var_dump($arrayIterator->current());Output:
string(5) "ready"Bounds are determined by the collection; verify the target position before seeking.
Practical Example: Applying the Feature
This example shows an application-style use of the feature, with its surrounding setup visible.
<?php
$arrayIterator = new ArrayIterator([10, 20, 30, 40]);
$arrayIterator->seek(1);
var_dump($arrayIterator->current());Output:
int(20)The code is shown for learning. Adjust the class names, inputs and error handling to suit your application.
Important Behavior and Edge Cases
- Bounds are determined by the collection; verify the target position before seeking.
- Moves the iterator to a requested numeric position; an invalid position can throw OutOfBoundsException.
- Observe differences in empty inputs, invalid states and optional extension availability where relevant.
Comparison With Related Approaches
| Approach | Important Difference |
|---|---|
ArrayIterator::seek | Moves the iterator to a requested numeric position; an invalid position can throw OutOfBoundsException. |
| ArrayObject | ArrayObject is a container that supplies an iterator, while ArrayIterator itself holds the cursor and traversal methods. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
Ignoring the documented state or precondition of ArrayIterator::seek | Bounds are determined by the collection; verify the target position before seeking. |
| Expecting a different type of result | Read the declared return type and distinguish returned values from changes to the source object. |
| Assuming a related API works identically | ArrayObject is a container that supplies an iterator, while ArrayIterator itself holds the cursor and traversal methods. |
Key Takeaways
- Moves the iterator to a requested numeric position; an invalid position can throw OutOfBoundsException.
- Bounds are determined by the collection; verify the target position before seeking.
- Use the example that matches the values, runtime version and dependencies in your application.
ArrayIterator::seek is useful when its behavior matches the data structure and lifecycle of your PHP application. Choose it with a clear understanding of its preconditions and returned values.