How to iterate through a Perl PDL piddle?

The closest I got to was something like

use PDL;
my $u = pdl [1,2,3,4];
my $dim = 4;
for(my $i=0; $i<$dim; $i++)
{
  print $u->fl开发者_如何学Pythonat->index($i), "\n";
}

Also as I can convert [1,2,3,4] to piddle $u, can I get back a list (or a list of lists for a matrix) from $u?

With the wisdom from the monks, I found the answer: http://perlmonks.org/index.pl?node_id=892201

Thought I'd share it here in my original question. The above code can be rewritten as:

use PDL;
my $u = pdl [1,2,3,4];
foreach ($u->dog)
{
  print $_, "\n";
}

The wisdom came with a disclaimer that dog() works only on small piddles (object).

besides using dog, here are two other options for your 1d pdl using index and list. there is also index2d

use PDL;
my $a = pdl(1 .. 4);
#use index
print $a->index($_), "\n" foreach (0 .. $a->nelem-1);
#use list
print $_ . "\n" foreach ($a->list);