Depth of AoAs

I have no clue why anyone might need this. I created it while answering a question about multidimensional arrays. It is my first successful recursive sub.

    sub depth {
        my $arr = shift;
        return 1 unless ref $$arr[0] eq 'ARRAY';
        return depth( $$arr[0] ) + 1;
    }
[download]

Call it with a reference to your array of arrays structure

print depth( \@array );

Update: Changed the fourth line to indicate the correct sub.

Comment on Depth of AoAs Select or Download Code

Replies are listed 'Best First'.
Re: Depth of AoAs by rob_au (Abbot) on Jan 14, 2002 at 10:33 UTC
There are two small problems with this code - The first is that you have called the subroutine `depth` yet reference it within the subroutine as `dimensions`. Has anyone ever told you that recursion is evil? :-) Also, if the subroutine is called with something other than an array reference, it still returns a count of 1. Update This code addresses the issues above and returns the correct reference depth of the array. `sub depth { return 0 unless ref $_[0] eq 'ARRAY'; return depth( ${$_[0]}[0] ) + 1; }` [download] Or alternatively, without recursion ... `sub depth { my $array = shift; my $count = 0; while (ref $array eq 'ARRAY') { $array = ${$array}[0]; ++$count; } return $count; }` [download] Update Okay ... So I was curious and went ahead and benchmarked these subroutines and was pleasantly surprised with the result. `Benchmark: timing 100000 iterations of loop, recursion... loop: 6 wallclock secs ( 5.30 usr + 0.00 sys = 5.30 CPU) @ 18 +867.92/s (n=100000) recursion: 6 wallclock secs ( 5.87 usr + 0.00 sys = 5.87 CPU) @ 17 +035.78/s (n=100000)` [download] Read more... (1244 Bytes)	[reply] [d/l] [select]
Re: Depth of AoAs by merlyn (Sage) on Jan 15, 2002 at 02:50 UTC
Hey, why is that taking so long to run on this? `my @x; push @x, \@x;` [download] {evil grin} -- Randal L. Schwartz, Perl hacker	[reply] [d/l]


good chemistry is complicated, and a little bit messy -LW
	PerlMonks