Get the maximum value from an element in a multidimensional array?

Question

I\'m trying to select the maximum value for a particular key in a multidimensional array. I\'m having trouble \"getting to\" the key in question...

So, the array (

Answer 1

If you like oneliners

$max = max( array_map(function( $row ){ return $row->dnum; }, $myarray) );