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PHP CachingIterator::getCache() Method: Usage and Examples

PHP CachingIterator::getCache() Method: Usage and Examples: Returns the entries retained by CachingIterator when FULL_CACHE is enabled. See three examples and important limitations.

1 views Published Oct 17, 2026 Updated Oct 17, 2026 admin

The PHP CachingIterator::getCache API performs a focused operation on an object or value. The examples below show its effect on actual data.

Returns the entries retained by CachingIterator when FULL_CACHE is enabled.

What Is CachingIterator::getCache in PHP?


Returns the entries retained by CachingIterator when FULL_CACHE is enabled.

Syntax:

CachingIterator::getCache()

This operation has no parameters.

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

$cachingIterator = new CachingIterator(new ArrayIterator(["pear" => 4, "apple" => 2, "plum" => 9]), CachingIterator::FULL_CACHE);
foreach ($cachingIterator as $item) {}
print_r($cachingIterator->getCache());

Output:

Array
(
    [pear] => 4
    [apple] => 2
    [plum] => 9
)

Returns the entries retained by CachingIterator when FULL_CACHE is enabled.

Example 2: A Different Input


A different set of values shows the same operation in another situation.

<?php

$cachingIterator = new CachingIterator(new ArrayIterator(["first" => "draft", "second" => "ready", "third" => "done"]), CachingIterator::FULL_CACHE);
foreach ($cachingIterator as $item) {}
print_r($cachingIterator->getCache());

Output:

Array
(
    [first] => draft
    [second] => ready
    [third] => done
)

The cache is populated during traversal and is not automatically complete at construction.

Practical Example: Applying the Feature


This example shows an application-style use of the feature, with its surrounding setup visible.

<?php

$cachingIterator = new CachingIterator(new ArrayIterator([10, 20, 30, 40]), CachingIterator::FULL_CACHE);
foreach ($cachingIterator as $item) {}
print_r($cachingIterator->getCache());

Output:

Array
(
    [0] => 10
    [1] => 20
    [2] => 30
    [3] => 40
)

The code is shown for learning. Adjust the class names, inputs and error handling to suit your application.

Important Behavior and Edge Cases


  • The cache is populated during traversal and is not automatically complete at construction.
  • Returns the entries retained by CachingIterator when FULL_CACHE is enabled.
  • Observe differences in empty inputs, invalid states and optional extension availability where relevant.

Comparison With Related Approaches


ApproachImportant Difference
CachingIterator::getCacheReturns the entries retained by CachingIterator when FULL_CACHE is enabled.
ArrayIteratorArrayIterator does not retain a separate cache of visited entries; CachingIterator can cache them when configured.

Common Beginner Mistakes


MistakeCorrect Approach
Ignoring the documented state or precondition of CachingIterator::getCacheThe cache is populated during traversal and is not automatically complete at construction.
Expecting a different type of resultRead the declared return type and distinguish returned values from changes to the source object.
Assuming a related API works identicallyArrayIterator does not retain a separate cache of visited entries; CachingIterator can cache them when configured.

Key Takeaways


  • Returns the entries retained by CachingIterator when FULL_CACHE is enabled.
  • The cache is populated during traversal and is not automatically complete at construction.
  • Use the example that matches the values, runtime version and dependencies in your application.

CachingIterator::getCache 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.

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