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copied!<p>(I just posted this as an answer to the <a href="https://stackoverflow.com/questions/9105816/is-there-a-way-to-detect-circular-arrays-in-pure-php">Is there a way to detect circular arrays in pure PHP?</a> question that @Cheery mentioned, but I may be updating that answer depending on that asker's needs.)</p> <p>The isRecursiveArray(array) method below detects circular/recursive arrays. It keeps track of which arrays have been visited by temporarily adding an element containing a known object reference to the end of the array. </p> <pre><code>function removeLastElementIfSame(array & $array, $reference) { if(end($array) === $reference) { unset($array[key($array)]); } } function isRecursiveArrayIteration(array & $array, $reference) { $last_element = end($array); if($reference === $last_element) { return true; } $array[] = $reference; foreach($array as &$element) { if(is_array($element)) { if(isRecursiveArrayIteration($element, $reference)) { removeLastElementIfSame($array, $reference); return true; } } } removeLastElementIfSame($array, $reference); return false; } function isRecursiveArray(array $array) { $some_reference = new stdclass(); return isRecursiveArrayIteration($array, $some_reference); } $array = array('a','b','c'); var_dump(isRecursiveArray($array)); print_r($array); $array = array('a','b','c'); $array[] = $array; var_dump(isRecursiveArray($array)); print_r($array); $array = array('a','b','c'); $array[] = &$array; var_dump(isRecursiveArray($array)); print_r($array); $array = array('a','b','c'); $array[] = &$array; $array = array($array); var_dump(isRecursiveArray($array)); print_r($array); </code></pre>

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