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CachingIterator::offsetExists

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

CachingIterator::offsetExistsThe offsetExists purpose

Description

public CachingIterator::offsetExists(string $key): bool
Warning

This function is currently not documented; only its argument list is available.

Parameters

key

The index being checked.

Return Values

Returns true if an entry referenced by the offset exists, false otherwise.

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User Contributed Notes 1 note

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ddrake at dreamingmind dot com
4 years ago
offsetExists($index) examines the cache, not the inner or outer iterator.

<?php
$cache
= new \CachingIterator(
new
\ArrayIterator(['a', 'b', 'c', 'd']),
\CachingIterator::FULL_CACHE);

$shortRange = range(0, 1);
$fullRange = range(0, 3);

foreach (
$shortRange as $index) {
$cache->next();
}

echo
PHP_EOL . 'The cache' . PHP_EOL;
var_export($cache->getCache());
echo
PHP_EOL;

foreach (
$fullRange as $offset) {
print_r("cache offset '$offset' " .
(
$cache->offsetExists("$offset") == 1
? 'exists'
: "doesn't exist"
) . PHP_EOL);
}
?>

The cache
array (
0 => 'a',
1 => 'b',
)
cache offset '0' exists
cache offset '1' exists
cache offset '2' doesn't exist
cache offset '3' doesn't exist
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