Richard Quadling wrote:
On 15 March 2010 23:45, Daevid Vincent <daevid@xxxxxxxxxx> wrote:
Anyone have a function that will return an integer of the number of
dimensions an array has?
/**
* Get the maximum depth of an array
*
* @param array &$Data A reference to the data array
* @return int The maximum number of levels in the array.
*/
function arrayGetDepth(array &$Data) {
static $CurrentDepth = 1;
static $MaxDepth = 1;
array_walk($Data, function($Value, $Key) use(&$CurrentDepth, &$MaxDepth) {
if (is_array($Value)) {
$MaxDepth = max($MaxDepth, ++$CurrentDepth);
arrayGetDepth($Value);
--$CurrentDepth;
}
});
return $MaxDepth;
}
Extending Jim and Roberts comments to this. No globals. By using a
reference to the array, large arrays are not copied (memory footprint
is smaller).
Using a reference actually increases overhead. References in PHP were
mostly useful in PHP4 when assigning objects would cause the object to
be copied. But even then, for arrays, a Copy on Write (COW) strategy was
used (and is still used) such that you don't copy any values. Try it for
yourself:
<?php
$copies = array();
$string = str_repeat( '*', 1000000 );
echo memory_get_usage()."\n";
for( $i = 0; $i < 1000; $i++ )
{
$copies[] = $string;
}
echo memory_get_usage()."\n";
?>
Cheers,
Rob.
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